Condition Analysis
AI-powered assessment using site data and 14-day weather history
Recent heavy rain on Aug 20 (11.6mm) followed by scattered showers and persistently high humidity means the rock has not had adequate continuous drying, and a major wet spell is forecast from tomorrow through Aug 30. Today offers marginal conditions at best on exposed south-facing formations, but internal moisture from the unsettled past week is a concern, and climbing is not recommended.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's scattered tower formations mean aspects vary dramatically between individual boulders — north-facing sides of towers will be significantly damper than south-facing sides even in the same area.
- The moorland setting means the ground around the base of formations holds moisture and can act as a reliable indicator of internal rock dampness — check the peat and soil at the base before touching rock.
- Some of the more famous formations (e.g. Idol Rock area, Cannon Rocks) have horizontal breaks and capping overhangs that channel water into seepage lines that can persist for days after heavy rain.
- The National Trust car park and access path can be muddy in wet spells; the open moorland position means mist and low cloud can deposit additional moisture not captured in rainfall data.
Warnings
2
- Heavy rain forecast tomorrow (12.2mm) and through the week — do not plan climbing sessions at Brimham until a sustained dry spell establishes after the front passes.
- Gritstone holds are at elevated breakage risk due to cumulative wetting — even if surfaces appear dry, internal moisture weakens the rock significantly.
Reasoning
The 11.6mm event on Aug 20 was followed by only partial drying with trace rain on Aug 22, and further scattered light rain on Aug 16–19 means the rock has been subjected to repeated wetting over the past 10 days with no sustained dry period exceeding 4 days.
Since the last significant rain on Aug 20, there have been 5 nominally dry days (Aug 23–25) but with humidity averaging 75–79% and moderate temperatures around 17–18°C, plus today's 0.2mm and high morning humidity, drying has been slow and incomplete despite the exposed position.
The cumulative wetting from multiple rain events (25.8mm in 28 days with several discrete events) means internal pore saturation is likely elevated, and gritstone holds are at increased risk of grain loosening and breakage.
Late August conditions are deteriorating with shorter days and cooling temperatures (average 13°C over the past week), reducing drying potential compared to peak summer, and the forecast wet spell will reset any drying progress.
Contributing Factors
7
11.6mm of rain on Aug 20 deeply saturated the rock, requiring 48–72+ hours of good drying conditions that have not been fully achieved.
Multiple rain events from Aug 16–20 (total ~19.1mm over 5 days) created cumulative saturation that single dry spells cannot fully reverse.
Humidity averaging 79% over the past week significantly impedes evaporative drying from the rock surface.
Brimham's open moorland setting provides consistent wind exposure (13–24 km/h) that meaningfully aids surface drying on windward faces.
The forecast shows 29mm of rain over the next 5 days starting tomorrow, which will completely reset any drying progress and deeply re-saturate the rock.
A trace 0.2mm around 14:00 today adds surface moisture and indicates unstable conditions, though the afternoon does dry out.
South and west-facing formations have had the best drying conditions, while north-facing towers will be notably damper.
Recommendations
3
- Do not climb today — the rock has not had sufficient drying since the recent wet period, and conditions are marginal even on the best-drying formations.
- Avoid Brimham entirely for the coming week as the forecast wet spell (29mm over 5 days) will deeply re-saturate the gritstone.
- Monitor conditions for a dry window after Sep 1 — you will need at least 48 hours of dry, breezy weather with low humidity before conditions become suitable again.
Previous Analyses
Marginal — Assess Conditions
60%
57 days ago
The last significant rain was 11.6mm on August 20th, followed by a trace of 0.3mm on the 22nd, giving roughly 2 full dry days with moderate temperatures and decent wind. South- and west-facing formations are likely dry enough to climb, but north-facing features and lower sections may still hold internal moisture, and a major wet spell is forecast from the 26th onwards.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's scattered tower and pinnacle formations mean each feature has its own micro-aspect — south-facing sides of towers can be bone dry while north-facing sides of the same boulder remain damp.
- The open moorland setting and 290m altitude mean overnight temperatures can drop sharply (4.3°C last night), producing heavy dew and condensation that re-wets surfaces each morning — aim for late morning onwards.
- Horizontal breaks, ledges, and the numerous crack systems across the formations act as moisture reservoirs; even after surface drying, jams and laybacks in cracks may encounter damp rock.
- The National Trust manages the site with conservation in mind — erosion damage to these iconic formations is highly visible and permanent; check the ground at the base of your chosen formation as a moisture indicator.
Warnings
2
- A substantial wet spell (nearly 50mm) is forecast from August 26th–29th; conditions will be unsafe for gritstone climbing from midweek through at least the end of the month.
- Overnight dew and condensation at this altitude mean early-morning rock surfaces will be wet even on dry days — do not assume dry weather means dry rock.
Reasoning
The 11.6mm rainfall on August 20th was the most significant recent event, preceded by several days of lighter rain (totalling ~8mm from Aug 16–19), meaning the rock was already moisture-loaded before the heavy fall; two dry days is marginal for full internal drying of gritstone after this cumulative wetting.
Two consecutive dry days with moderate westerly/easterly winds (14–20 km/h) and temperatures around 15–18°C on an exposed moorland site provide reasonable surface drying, and the south/west-facing formations will have benefited most, but north-facing aspects at 290m altitude with 73–78% humidity will have dried much more slowly.
After cumulative rainfall of ~20mm over Aug 16–20, internal moisture levels in some formations could still be above the threshold where significant strength loss occurs, particularly in north-facing or sheltered rock, posing a risk of grain loosening and hold damage.
Mid-to-late August is generally favourable for drying, though the recent spell of cooler, damper weather (averaging only 12.7°C over the last week with 80% humidity) has reduced the seasonal advantage, and a substantial wet spell is forecast from the 26th.
Contributing Factors
7
11.6mm fell on already-moist rock after several days of lighter rain, requiring extended drying time for full recovery.
August 22nd (trace only) through today gives roughly 48 hours of drying — marginal but approaching the minimum threshold for lighter accumulations on exposed rock.
Brimham's highly exposed position with consistent 14–20 km/h winds significantly accelerates evaporative drying compared to sheltered valley crags.
South-facing formations will have dried well but north-facing sides of towers and shaded gullies between formations will lag considerably behind.
Overnight lows of 4.3°C with humidity reaching 94% produce heavy dew and condensation, effectively re-wetting rock surfaces each morning.
Nearly 50mm of rain is forecast over the coming days, meaning today and tomorrow represent a narrow window before conditions deteriorate significantly.
Approximately 20mm fell between Aug 16–20, meaning the rock was repeatedly wetted before the main 11.6mm event, increasing internal saturation levels.
Recommendations
3
- Focus on south- and west-facing formations where solar exposure and prevailing wind will have provided the best drying — avoid north-facing problems and shaded gullies between towers.
- Check the ground at the base of your chosen formation: if the soil or peat is damp, the rock likely retains internal moisture and should be left alone.
- Plan to climb from late morning onwards (after 11:00) once dew and overnight condensation have burned off, and consider this a brief window before major rain arrives midweek.
Do Not Climb
40%
58 days ago
Heavy rain (11.6mm) fell just three days ago on August 20th, followed by further light precipitation on the 22nd, and only one full dry day has elapsed since. Despite the exposed position of Brimham, the combination of moderate temperatures, high average humidity (83%), and limited drying time means the rock is very likely still holding internal moisture, particularly on north-facing formations and lower sections.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's towers and pinnacles have all aspects — north-facing sides and shaded alcoves between formations will retain moisture far longer than the exposed south-facing surfaces.
- Many of the lower problems and routes sit close to the peaty moorland ground, which acts as a moisture reservoir and slows drying at the base of formations.
- The balanced boulders and overhanging features (e.g. Cubic Block area) will have shed water quickly and may dry faster than the slabs and crack lines that channel seepage.
- National Trust site with seasonal access considerations — check NT website for any path or area closures before visiting.
Warnings
2
- Do not climb on any visibly damp rock or where the peat/ground at the base of formations is wet — surface-dry gritstone can still be dangerously weakened internally.
- A major rainfall event (48mm + 25mm) is forecast for August 27–28; plan around this and expect the crag to be out of condition for several days afterward.
Reasoning
With 11.6mm of heavy rain on August 20th, followed by trace/light precipitation on the 22nd and only one dry day since, the gritstone is very likely still holding significant internal moisture despite any surface drying.
One full dry day with moderate wind (13–19 km/h) and temperatures around 15–18°C at 73–76% humidity provides insufficient drying for porous Millstone Grit after a heavy soaking — the exposed position helps but cannot compensate for the high humidity and limited time.
Internal moisture from the recent heavy rain poses a real risk of grain loosening and hold breakage, especially on well-trafficked popular problems where the rock sees heavy use.
Mid-to-late August conditions are reasonable for drying in principle, but the recent wet spell with high humidity and below-average temperatures has significantly slowed the drying process.
Contributing Factors
6
11.6mm fell on August 20th — a significant soaking event requiring 48–72+ hours of good drying conditions, and additional light rain (0.3mm) fell on the 22nd resetting the surface.
Only one consecutive dry day has passed since the last precipitation, well short of the minimum 48–72 hours needed after heavy rain on porous gritstone.
Average humidity over the last 7 days is 83%, severely limiting evaporative drying potential from the rock surface.
Brimham's exposed hilltop position with consistent winds (13–24 km/h) accelerates surface drying relative to sheltered valley crags.
Temperatures around 15–18°C are adequate for some evaporation but not strongly driving rapid drying, especially combined with high humidity.
While south-facing surfaces benefit from solar drying, many formations have north and east-facing sides that will dry much more slowly and remain damp longest.
Recommendations
3
- Wait at least another 1–2 full dry days before climbing; if you visit tomorrow or the day after, physically check rock surfaces and the ground at the base of formations before committing.
- Prioritise south and west-facing overhanging features on exposed towers if you do assess conditions as climbable — avoid north-facing slabs, crack lines, and lower sections entirely.
- Be aware that very heavy rain is forecast for August 27–28 (73+ mm combined), which will reset conditions completely and require an extended drying period afterward.
Do Not Climb
35%
59 days ago
Heavy rain of 11.6mm on August 20th followed by only one full dry day (Aug 21) and a trace of rain today means the gritstone is very likely still holding significant internal moisture. Despite Brimham's exposed position aiding drying, the recent wet spell (19.3mm in the last 7 days) with high humidity has not allowed adequate drying time — we recommend waiting.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's scattered towers and pinnacles have highly variable aspects — north-facing formations and sheltered recesses between boulders will retain moisture far longer than exposed south-facing faces after the recent heavy rain.
- The open moorland setting means the peat and heather at the base of formations acts as a moisture reservoir, keeping lower sections of rock damp even when upper sections feel dry.
- National Trust site with seasonal access considerations — check for any path or crag closures, and be mindful that the NT car park has opening hours and charges.
- Some of the famous balanced boulders and pinnacles (e.g. Idol, Cubic Block) have horizontal surfaces and capping overhangs that channel water down specific seepage lines, which can remain wet for days after heavy rain.
Warnings
2
- The rock surface may appear dry while still holding dangerous levels of internal moisture from the 11.6mm rain on August 20th — do not rely on visual assessment alone.
- Climbing on wet gritstone causes permanent, irreversible damage to holds and routes at this irreplaceable venue.
Reasoning
With 11.6mm of heavy rain on Aug 20th, followed by only one genuinely dry day and a trace today, the gritstone is almost certainly still holding significant internal moisture despite surface drying.
Only ~36 hours of meaningful drying since the heavy rain, with moderate winds (18–19 km/h) but high humidity (77–78%) and cool temperatures (~14–16°C) severely limiting evaporation rates — well short of the 48–72+ hours needed after heavy rain.
At current estimated moisture levels the rock is likely in the danger zone where 80% of compressive strength loss occurs, meaning holds could break under load even if surfaces appear dry.
Mid-to-late August conditions are reasonable for drying but the recent cool, humid spell with average temperatures of only 13.3°C and 83% humidity over the last week has significantly slowed what would normally be adequate summer drying.
Contributing Factors
7
11.6mm fell on August 20th — the heaviest single-day rainfall in the past month — requiring a minimum of 48–72 hours of good drying conditions.
Only approximately 36 hours since the heavy rain, with a trace of rain today resetting the clock, falling well short of the minimum 48-hour guideline.
Average humidity of 83% over the last 7 days severely impedes evaporation, meaning drying is much slower than the wind exposure alone might suggest.
Average temperature of only 13.3°C over the past week is low for August and significantly reduces evaporation rates.
Brimham's exposed moorland position with consistent winds of 16–24 km/h helps accelerate surface drying on windward faces.
Multiple days of rain from Aug 16–20 totalling 19.1mm mean the rock has been repeatedly re-wetted before any single event could fully dry out.
South and west-facing formations will dry fastest, but the site's all-aspect nature means many formations face north or east and will retain moisture significantly longer.
Recommendations
3
- Wait at least until August 24th before considering a visit, allowing a minimum of 48+ hours of dry weather after today's trace precipitation.
- If visiting after adequate drying, prioritise south-facing and west-facing exposed formations and test the base of the rock — if the ground or lower rock is damp, do not climb.
- Check the National Trust website for any access updates and consider the car park opening times when planning your visit.
Do Not Climb
30%
60 days ago
Heavy rain of 11.6mm fell yesterday (Aug 20) followed by continued light precipitation today, with high humidity averaging 82% over the past week. The rock is almost certainly still saturated internally despite Brimham's exposed position, and conditions are not suitable for climbing on gritstone.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's scattered tower and pinnacle formations mean different blocks will dry at very different rates — south-facing exposed pinnacles dry fastest while north-facing recesses and lower boulder bases can stay damp for days.
- The open moorland setting provides excellent wind exposure which is a major drying advantage, but the surrounding heather and peat moorland holds moisture and can maintain locally elevated humidity at crag level.
- Many of Brimham's classic problems are on lower sections of boulders and near ground level where drainage from above keeps the rock damp longest — check these carefully even when upper faces appear dry.
- As a National Trust site, access is generally reliable but car park charges apply; check NT website for any seasonal event closures.
Warnings
2
- Do not climb today — the rock is almost certainly saturated after 11.6mm of rain yesterday and continued wet conditions; climbing risks permanent hold breakage on these irreplaceable gritstone formations.
- The preceding week (Aug 16–20) saw repeated rain events totalling 19.2mm, meaning the rock has had little opportunity to dry internally even if surfaces appear dry in coming days.
Reasoning
11.6mm of heavy rain on Aug 20 followed by trace precipitation today means the rock is almost certainly still saturated internally, with only ~24 hours of marginal drying since the heaviest rain.
Despite Brimham's exposed position, moderate wind (16–24 km/h) and cool temperatures (~14°C) combined with high humidity (78–90%) provide only slow drying conditions — nowhere near the 48–72+ hours of dry weather needed after 10mm+ rain.
With the rock likely above 60% pore saturation from yesterday's heavy rain and the preceding wet week (19.2mm in 7 days), there is significant risk of hold breakage and grain loosening on these gritstone formations.
Mid-to-late August is generally a reasonable season for climbing but the current unsettled spell with below-average temperatures (~14°C) is slowing drying significantly compared to typical summer conditions.
Contributing Factors
6
11.6mm fell on Aug 20 with additional light rain on Aug 16–19, totalling 19.2mm in the last 7 days — well above the threshold requiring 48–72+ hours of dry weather.
Only ~24 hours since heavy rain with trace precipitation still occurring today, far short of the minimum 48–72 hours needed after heavy rain on porous gritstone.
Average humidity of 82% over the past week with today at 78% significantly limits evaporative drying potential.
Temperatures averaging only 13.7°C over the past week slow evaporation rates compared to warmer summer conditions.
Brimham's open moorland position provides consistent wind exposure (16–25 km/h) which is the primary positive drying factor, though insufficient to overcome the moisture deficit.
South and west-facing formations will dry faster than north-facing ones, but with such recent heavy rain no aspect is likely to be adequately dry yet.
Recommendations
3
- Wait at least until Aug 23–24 before considering climbing, allowing a minimum of 48–72 hours of dry weather after the heavy rain on Aug 20.
- When you do visit, test conditions by checking the ground at the base of formations — if the soil or peat is damp, the rock is almost certainly still wet internally.
- Prioritise south and west-facing exposed pinnacles and upper sections which will dry first; avoid north-facing faces, lower boulder sections, and any routes near seepage lines or drainage channels.
Do Not Climb
95%
61 days ago
Brimham Rocks received 14.3mm of heavy rain today on top of an already wet week (23.1mm in 7 days), and the rock will be thoroughly saturated. Climbing today and tomorrow is not appropriate; meaningful drying cannot begin until at least August 22nd.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's scattered tower and pinnacle formations mean many faces are sheltered from wind by adjacent blocks, so exposed-moorland drying rates don't apply uniformly — check sheltered sides and lower sections carefully.
- North-facing aspects of the towers (e.g. Cubic Block, Cannon Rock north side) will retain moisture significantly longer than south-facing faces after this heavy soaking.
- The horizontal bedding planes and cracks characteristic of Brimham's formations act as reservoirs, holding water internally long after surfaces appear dry — seepage from these features is common for days after heavy rain.
- National Trust manage the site and climbing is by permission; climbing on wet rock risks both route damage and access restrictions — respect the ethics to preserve this unique venue.
Warnings
2
- 14.3mm of rain today on already-wet rock means all holds and features are severely weakened — climbing now risks permanent damage to routes and serious injury from hold failure.
- The rock surface may appear to dry in wind during the afternoon but internal saturation remains dangerously high — do not be deceived by surface appearance.
Reasoning
With 14.3mm of rain today following 8.8mm over the preceding four days (Aug 16–19), the gritstone is fully saturated throughout, with internal moisture levels far above the critical 1% threshold for significant strength loss.
Meaningful drying cannot begin until the rain stops; the last significant precipitation today was around 10:00, but scattered showers continue through the afternoon and evening, and tomorrow brings another 0.5mm — effective drying only starts on August 22nd, meaning at least 48 hours of drying from the last rain by late August 23rd.
At full saturation the gritstone could have lost 30–50% of its compressive strength, making hold breakage a serious risk on the finer features and edges that characterise many Brimham problems.
Summer temperatures and the exposed position are favourable for drying once rain ceases, but the current cool spell (14–15°C) and elevated humidity (80%+) will slow the process compared to the warm dry spell seen earlier in August.
Contributing Factors
7
14.3mm of rain today is a significant soaking event that will have fully saturated the porous gritstone.
23.1mm over the last 7 days means the rock had no opportunity to dry fully before today's downpour, compounding saturation.
Average humidity of 87% today with near-100% overnight severely limits any evaporative drying.
Temperatures of only 14–15°C are well below the 20°C+ seen earlier in August, slowing evaporation rates.
Sustained westerly/northerly winds of 20–25 km/h will aid drying once precipitation stops, particularly on exposed south and west faces.
Two dry days with lower humidity (73–76%) and light wind are forecast for August 22–23, offering a drying window.
Rain returns on August 24th (0.6mm) and heavily on August 25th (13.8mm), cutting short the drying window.
Recommendations
3
- Do not climb today or tomorrow — the rock is fully saturated and structurally weakened.
- The earliest realistic window to assess conditions is the afternoon of August 23rd, after roughly 36–48 hours of dry weather, but only on exposed south-facing faces.
- Be aware that heavy rain is forecast again on August 25th, so any climbing window around August 23rd will be brief — plan accordingly and check conditions carefully on arrival.
Do Not Climb
90%
62 days ago
Brimham Rocks has received rain today and over the past several days (3.1mm on Aug 16, 0.9mm on Aug 17, 1.2mm on Aug 18, and 2.3mm today), with no meaningful dry spell in between. Tomorrow's forecast of 32.3mm of heavy rain will thoroughly saturate the rock, making conditions clearly unsuitable today and for several days ahead.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's scattered tower and pinnacle formations mean many faces have sheltered, north-facing sides that dry significantly slower than the exposed south-facing aspects — avoid assuming all formations are equally dry.
- The open moorland position and 290m altitude provide excellent wind exposure that genuinely accelerates drying on south and west faces, but the numerous crevices, chimneys, and undercuts between formations act as moisture traps.
- Many popular problems at Brimham have low landings on peaty moorland soil — if the ground is boggy or the peat is saturated, the rock above is almost certainly still holding internal moisture.
- National Trust ownership means access is generally reliable, but the car park has closing times and the site is popular with tourists; early starts on weekdays offer the best climbing experience.
Warnings
2
- A 32.3mm rain event forecast for August 20 will heavily saturate the gritstone — do not climb on or immediately after this day.
- The rock may appear surface-dry on south-facing aspects within a day of rain stopping, but internal moisture will still be dangerously high; allow a full 48 hours minimum after the last rain.
Reasoning
The rock has received intermittent rain over the past four days (Aug 16–19 totalling ~7.5mm) with high humidity throughout, meaning the gritstone is currently wet both on the surface and internally.
There has been no consecutive dry period since Aug 10–15 sufficient to fully dry the rock; the modest westerly winds (13–26 km/h) and moderate temperatures (~16–17°C) have been insufficient to counteract repeated wetting events and humidity averaging 76%.
With repeated wetting over the past several days and a massive 32.3mm rain event forecast tomorrow, the gritstone will be at or near saturation — climbing risks significant hold breakage and permanent surface damage.
Mid-August should be prime climbing season but this unsettled spell with cool temperatures (14–17°C) and elevated humidity is delaying drying considerably; freeze-thaw is not a concern at current temperatures.
Contributing Factors
6
Today has already seen 2.3mm of precipitation spread through the morning with further light showers forecast this evening, keeping the rock actively wet.
A major 32.3mm rainfall event is forecast for August 20, which will thoroughly saturate the gritstone and reset any drying progress.
Rain on Aug 16 (3.1mm), 17 (0.9mm), 18 (1.2mm), and today (2.3mm) means the rock has had no opportunity to dry internally over the past four days.
Average humidity of 76% over the last week severely limits evaporative drying even with wind exposure.
Brimham's moorland exposure and consistent westerly winds (20–26 km/h) will help accelerate drying once the rain stops, particularly on south and west faces.
Temperatures of 15–17°C are adequate for drying but not exceptional; the cooler conditions since Aug 16 have slowed evaporation compared to the warm spell earlier in the month.
Recommendations
3
- Do not climb today or in the next two days — the rock is currently wet and heavy rain tomorrow will fully saturate the gritstone.
- After the rain clears on Aug 21, allow at least 48 hours of dry weather before considering climbing; south-facing exposed formations may dry first from Aug 23 onwards.
- Check ground conditions at the base of formations as a proxy for internal rock moisture — if the peat and soil are still damp, the rock is not ready.
Do Not Climb
90%
63 days ago
Brimham Rocks is currently wet and unsuitable for climbing. Rain fell overnight and yesterday (1.4mm today, 1.7mm on Aug 17, 3.1mm on Aug 16), with further rain forecast tomorrow (2.2mm) and a heavier band on Aug 20 (9.2mm) — there has been no meaningful drying window and none is expected until Aug 21 at the earliest.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's scattered formations mean some faces are heavily sheltered by adjacent towers and overhangs, creating micro-environments that dry much slower than the exposed tops — check lower buttress faces and north-facing alcoves especially carefully.
- The moorland setting means drainage can be poor at ground level; persistent boggy conditions around the base of formations are a reliable indicator that the rock still holds internal moisture.
- With all-round aspects, south- and west-facing faces will recover first after the rain clears on Aug 21, while north-facing problems and shaded gullies between formations may need an extra day or two.
- National Trust site with open access but heavy visitor footfall — climbing on damp gritstone here causes visible polishing and hold damage that is noticed and can affect the climbing community's relationship with the Trust.
Warnings
2
- Climbing on wet gritstone causes permanent hold damage and accelerated erosion — do not climb even if surfaces appear superficially dry after only a few hours.
- The heavy rain forecast for Aug 20 (9.2mm) will fully re-saturate the rock; treat Aug 21 as day zero of the drying clock.
Reasoning
The rock is currently wet: rain fell overnight (0.9mm early hours), following 3.1mm on Aug 16 and 1.7mm on Aug 17, with no dry period of any meaningful length since Aug 15.
Despite decent westerly winds (20–27 km/h), persistent high humidity (85–97% overnight, 67–82% during the day) and complete cloud cover have prevented any effective drying, and further rain tomorrow and Aug 20 will re-saturate the rock.
The gritstone is almost certainly holding significant internal moisture from three consecutive days of rain with no drying opportunity, placing holds at meaningful risk of breakage under load.
Mid-August temperatures (15–17°C) are adequate for drying when rain stops, but the current unsettled spell with high humidity and full cloud cover negates these seasonal advantages.
Contributing Factors
6
Rain has fallen on each of the last three days (3.1mm, 1.7mm, 1.4mm) with no consecutive dry hours long enough for meaningful drying.
Humidity has been 85–97% overnight and 65–86% during the day, severely limiting evaporative drying even with wind.
Sustained westerly winds of 20–27 km/h would normally accelerate drying, but cannot overcome the persistent moisture input and high humidity.
2.2mm is forecast for Aug 19 and a significant 9.2mm on Aug 20, meaning no drying window exists until Aug 21 at the earliest.
100% cloud cover throughout the day eliminates solar heating of the rock surface, further slowing any drying.
Temperatures of 15–17°C are warm enough to support drying when conditions allow, but are currently offset by humidity and cloud.
Recommendations
3
- Do not climb today or over the next two days — the rock is wet and further rain is incoming.
- The earliest realistic window is Aug 22, after a full dry day on Aug 21 with dropping humidity; south- and west-facing formations should be assessed first.
- If visiting Aug 22–23, test conditions by checking that the ground around the base of formations is sandy-dry and that the rock feels warm and gritty, not cool and smooth.
Do Not Climb
70%
64 days ago
Brimham received 3.4mm of rain yesterday (Aug 16) and 1.5mm today with further light rain forecast this evening; the rock has had virtually no drying time and humidity is very high. With 4.1mm forecast tomorrow and a heavy 19.1mm event on Aug 20, conditions are poor now and will worsen before they improve.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's scattered formations mean some sheltered north-facing boulders and recessed cracks will retain moisture far longer than the exposed south-facing towers, so conditions vary hugely across the site.
- The open moorland position and 290m altitude mean wind-assisted drying can be effective, but today's very light winds (2–10 km/h) are not providing meaningful drying benefit.
- Many classic problems at Brimham have polished landings and seepage lines at the base of formations — if the peat and grass around the boulders is damp, the rock is almost certainly still wet internally.
- National Trust site with high visitor traffic; climbing on damp gritstone here risks visible damage to iconic formations, which could jeopardise access.
Warnings
2
- Gritstone loses significant strength even at very low moisture levels — the surface may feel dry while the interior is still saturated and vulnerable to hold breakage.
- A heavy 19.1mm rain event is forecast for Aug 20; climbing before this clears and the rock fully dries would risk permanent damage to these iconic National Trust formations.
Reasoning
Rain fell yesterday (3.4mm) and early today (0.4mm at midnight, with 0.2mm more forecast this evening), so the rock is currently wet or only superficially drying, especially given 86% average humidity today.
With less than 24 hours since the last meaningful rain (3.4mm on Aug 16), very light winds today (mostly 2–10 km/h), and persistently high humidity (77–97%), the rock has had negligible effective drying — well short of the 24–48 hour minimum required after light rain.
Gritstone weakens significantly even at low saturation levels, and the recent rain combined with high humidity means internal moisture is almost certainly still present, posing hold breakage and grain loosening risks.
Mid-summer temperatures (15–19°C) are adequate for drying in principle, but the current spell of unsettled, humid weather with overcast skies is suppressing evaporation rates.
Contributing Factors
6
3.4mm fell on Aug 16 and 1.5mm today, giving the rock less than 24 hours of drying — far below the 24–48 hour minimum for light rain on gritstone.
Humidity has been 77–97% throughout today with 100% cloud cover, severely limiting evaporation from the rock surface.
Winds are only 2–10 km/h today, unusually calm for this exposed site, reducing the wind-assisted drying that Brimham normally benefits from.
4.1mm is forecast for Aug 18, meaning any drying progress today will be reversed before meaningful drying can occur.
A substantial 19.1mm event is forecast for Aug 20, which will thoroughly saturate the rock and require 48–72+ hours of dry weather to recover from.
Temperatures of 15–19°C are reasonable for drying, but the benefit is negated by high humidity, cloud cover, and lack of wind.
Recommendations
3
- Do not climb at Brimham today — the rock has not had sufficient drying time since yesterday's 3.4mm rain and conditions will worsen with rain tonight and tomorrow.
- The earliest realistic window is Aug 22 onward, but only if the heavy rain on Aug 20 clears as forecast and at least 48 hours of dry, breezy weather follows — check forecasts again on Aug 21.
- If visiting the area, consider non-porous alternatives such as limestone or whinstone crags, which do not suffer structural damage when damp.
Marginal — Assess Conditions
72%
65 days ago
Brimham has had an excellent extended dry spell from August 8–15 with warm temperatures and good winds, but today (Aug 16) has seen 0.4mm of light rain. The rock should be fundamentally dry from the prolonged drying period, but today's moisture may leave a surface film on some aspects — a visual check on arrival is warranted.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Brimham's exposed moorland position and mixed aspects mean south- and west-facing formations will have dried rapidly during the warm Aug 12–14 spell (up to 32°C), while north-facing features may retain traces of moisture longer.
- The scattered tower and pinnacle formations create variable micro-climates — sheltered alcoves between boulders and moss-covered bases can hold dampness even when open faces are bone-dry.
- The National Trust site has well-drained sandy/peaty moorland ground, so the base-of-crag moisture test is a useful indicator — if the peat at the base is dry and firm, the rock is almost certainly dry internally.
- Some of the lower-lying boulders and north-facing slabs at Brimham are prone to seepage from the moorland above, particularly after any recent rain, so these should be checked individually.
Warnings
1
- More rain is forecast from Aug 17–20 (cumulative ~3.5mm), so conditions will likely deteriorate over the coming days — today or early tomorrow may be the best window before the next wet spell.
Reasoning
The rock benefited from a superb 5-day drying window (Aug 11–15) with temperatures reaching 32°C, low humidity (53–70%), and consistent winds, meaning internal moisture from earlier August rain (3.7mm on Aug 4, 1.6mm on Aug 5) will have been thoroughly driven off — today's 0.4mm is trivial but introduces fresh surface moisture.
Today's 0.4mm in the context of an exposed, windy site with 17°C temperatures should dry from sun- and wind-exposed surfaces within hours, but sheltered north-facing features and recesses may need until tomorrow morning to fully shed surface dampness.
Structural risk is very low — the extended dry spell ensured deep internal drying, and today's trace rain cannot meaningfully re-saturate the rock; hold integrity is not a concern.
Mid-August is peak climbing season with long days, warm temperatures, and no freeze-thaw risk; conditions are broadly favourable despite the passing shower today.
Contributing Factors
6
Five consecutive fully dry days (Aug 11–15) with exceptional warmth (up to 32°C) and steady winds thoroughly dried the rock after earlier August rain.
0.4mm today introduces minor surface moisture that may linger on sheltered or north-facing features into this evening.
Consistent 15–26 km/h westerly winds across the open moorland significantly accelerate surface and near-surface drying.
South- and west-facing formations will dry quickly from today's drizzle, but north-facing slabs and sheltered alcoves between boulders may retain dampness longer.
Humidity at 72% is moderate and slightly limits evaporation rate, though wind compensates substantially at this exposed site.
Temperatures around 17°C today and averaging 17.5°C over the past week provide adequate warmth for effective drying with no freeze-thaw risk.
Recommendations
3
- South- and west-facing formations are the best bet today and tomorrow — visually inspect and touch-test the rock surface before committing, especially any holds in recesses or horizontal breaks.
- Avoid north-facing slabs, moss-covered features, and lower boulders near ground-level seepage until at least 24 hours after the last rain.
- Check the peat/ground at the base of your chosen formation — if it's soggy, choose a different, more exposed feature.
Climbing Outlook