Condition Analysis
AI-powered assessment using site data and 14-day weather history
Today saw rain arriving mid-afternoon after a dry morning, and the rock will be wet into the evening; the forecast for the coming days shows a prolonged and heavy wet spell with over 70mm expected, making conditions unsuitable for the foreseeable future.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's persistent seepage lines will be actively running given the 40mm+ of rain in the last week and heavy rain forecast, making routes on that buttress particularly slippery.
- The W/NW aspect means the crag misses morning sun entirely, relying on afternoon sun for drying — but 100% cloud cover today and in the forecast negates this advantage.
- Castle Rock sits at 300m in St John's in the Vale where valley-funnelled cloud and mist frequently linger, keeping humidity high and suppressing evaporation even between showers.
- Check for peregrine nesting restrictions before visiting — spring restrictions may still occasionally apply into late summer if nesting is late.
Warnings
2
- Active seepage lines on the north crag will make several classic routes dangerously slippery even if main faces appear superficially dry.
- The sustained wet period increases the risk of greasy, lichen-covered holds — take extra care on any visit after this spell ends.
Reasoning
The rock received 3.5mm of rain this afternoon (14:00–16:00) following a brief dry window of only 4 days (Aug 22–25), and prior to that a very wet period with 34mm on Aug 19–20 alone — seepage lines on the north crag will be active and surfaces damp.
With 100% cloud cover, high humidity (80–95%), and only moderate easterly winds that don't directly ventilate the W/NW-facing rock, meaningful drying is unlikely before tomorrow's heavy rain arrives.
Borrowdale Volcanic Series rhyolite is non-porous so structural damage from moisture is not a concern; the risk is entirely friction loss on wet or damp surfaces.
Late August conditions are deteriorating with shorter days, lower sun angles, and an increasingly unsettled Atlantic weather pattern — the forecast 73mm over the next 5 days is typical of autumn's early arrival in the Lakes.
Contributing Factors
7
3.3mm of rain fell between 14:00 and 16:00 today, wetting the rock surface after a dry morning window.
11.8mm forecast for Aug 27 with 91% humidity will keep the crag thoroughly wet.
34.6mm forecast for Aug 28 represents a very heavy rainfall event that will saturate every surface and activate all seepage lines.
Humidity has averaged 83% over the past week and remains above 85% in forecasts, severely limiting evaporative drying.
Complete cloud cover today and likely through the forecast period eliminates solar drying on the W/NW-facing crag.
Easterly winds at 15–26 km/h provide some airflow but do not directly ventilate the west-facing rock effectively.
BVS rhyolite does not absorb water, so once rain stops and surfaces dry, friction recovers fully — but that drying window is not available this week.
Recommendations
3
- Avoid climbing today and for the rest of this week — the prolonged wet spell with 73mm forecast makes safe, dry conditions extremely unlikely before September.
- If visiting the area, consider low-level indoor alternatives in Keswick; Castle Rock's seepage lines will need at least 24–48 hours of dry, breezy weather after the rain ends to clear.
- Monitor conditions around Sep 1 when the forecast shows a potential dry day — but wait for confirmation of actual drying before committing to routes on the north crag.
Previous Analyses
Marginal — Assess Conditions
72%
57 days ago
After three consecutive dry days following a very wet spell (21.7mm on Aug 19, 12.7mm on Aug 20), the non-porous BVS rock surface should be largely dry today, especially on exposed faces with afternoon sun and moderate wind. However, seepage lines on the north crag may still be active given the heavy recent rainfall, so a visual check on arrival is essential.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines are likely still weeping after 40mm of rain in the last 7 days, particularly from the heavy 21.7mm event on Aug 19 — avoid routes intersecting drainage features.
- The W/NW aspect means the crag receives no direct sun until afternoon; morning sessions will rely solely on wind for drying, so plan to climb from midday onward for best friction.
- Peregrine nesting restrictions may still be in effect at this time of year — check the BMC RAD or local notices before approaching restricted sections.
- Today's SE wind does not directly hit the W/NW-facing crag, reducing its drying effectiveness compared to the prevailing westerlies seen earlier in the week.
Warnings
2
- Seepage lines on the north crag may still be active — test friction carefully on the first few moves of any route before committing to sustained climbing.
- A major wet spell begins Aug 26 with nearly 63mm forecast over four days; do not plan crag visits from Aug 26–29.
Reasoning
Three full dry days with moderate wind have elapsed since the last significant rain, and the non-porous BVS rock surface should have shed most surface moisture, though localised seepage from the heavy Aug 19–20 rainfall (34.4mm combined) may persist in drainage channels.
Today's SE wind offers less direct drying on the W/NW-facing crag than the westerlies earlier this week, but humidity has dropped to 53–66% with clear skies, providing reasonable evaporative conditions from midday onward.
No structural risk — Borrowdale Volcanic Series rock is non-porous and does not weaken when wet; the concern is purely friction loss on any residual damp patches.
Mid-to-late August offers adequate daylight for a full climbing day, though temperatures are cool for summer (max ~16°C) and the approaching wet spell from Aug 26 onward will close the window quickly.
Contributing Factors
6
No precipitation since Aug 21 (2.2mm), with two fully dry days before today giving the rock time to shed surface water.
40.1mm fell in the last 7 days including a 21.7mm deluge on Aug 19, which will have charged seepage lines and drainage features on the north crag.
Humidity drops to 53% by mid-afternoon with 0% cloud cover through midday, promoting strong evaporative drying on exposed surfaces.
Today's SE wind direction does not impinge directly on the W/NW-facing rock, reducing the wind's drying benefit compared to prevailing westerlies.
The west-facing aspect will receive direct afternoon sun from around midday, warming the rock and accelerating evaporation of any lingering dampness.
Over 62mm of rain is forecast from Aug 26–29, meaning today and tomorrow represent the only viable climbing window for at least a week.
Recommendations
3
- Aim to climb from midday onward when the afternoon sun has warmed the west-facing rock and humidity is at its lowest.
- Visually inspect routes for seepage lines and damp patches before committing, especially on the north crag — carry a towel and be prepared to bail.
- Take advantage of today and tomorrow as the last dry window; heavy rain from Aug 26 will make the crag unsuitable for several days.
Marginal — Assess Conditions
62%
58 days ago
After two dry days following a very wet spell (34.4mm on Aug 19–20), the main rock faces should be largely dry given BVS rock's non-porous nature and moderate wind, but persistent seepage lines on the north crag and high ambient humidity (80%+) mean conditions should be checked on arrival. A major deterioration is forecast from Aug 27 with over 70mm of rain expected.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines may still be running after the heavy rain on Aug 19–20 (34.4mm combined), and the NW aspect receives limited direct sun to dry these features.
- The west-facing aspect means the crag will only receive direct afternoon sun, so morning visits may find residual dampness on holds especially in shaded recesses.
- Peregrine nesting restrictions should be checked before visiting — though the main nesting season is typically over by late August, late broods are possible.
- The crag's 300m altitude and recent cool temperatures (averaging just 10.3°C over the past week) slow evaporation compared to valley-floor crags.
Warnings
2
- Very heavy rain is forecast for Aug 27–28 (over 70mm combined) — conditions will be unsafe for climbing and approach paths may flood; do not plan trips for those dates.
- North crag seepage lines may still be active despite surface drying — test friction carefully before committing to steep ground.
Reasoning
Two full dry days with moderate wind have elapsed since the last significant rain, and BVS rock does not absorb water, so exposed surfaces should be dry but sheltered seepage zones and recesses may retain moisture.
Westerly/SW winds at 12–16 km/h provide moderate surface drying, but the W/NW aspect limits direct sun exposure to afternoon hours only, and humidity has remained around 80–84%, slowing full evaporation in shaded areas.
No structural risk — Borrowdale Volcanic Series rock is non-porous and does not suffer hold weakening or breakage from moisture.
Late August in the Lake District brings shortening days and increasing moisture; the recent pattern of frequent rain with brief dry windows is typical and the forecast suggests this pattern is intensifying.
Contributing Factors
6
No precipitation since Aug 21 (2.2mm), giving the non-porous rock two full days to shed surface water.
34.4mm fell on Aug 19–20 and 45.7mm total in the last 7 days, which will sustain seepage lines longer than a brief shower would.
Humidity has averaged 89% over the past week and remains at 80% today, slowing evaporation from shaded features and seepage zones.
Average temperature of just 10.3°C at 300m over the past week provides limited evaporative energy.
Consistent 10–20 km/h winds across the partially exposed crag aid surface drying on the main faces.
The volcanic rock sheds water from its surface rather than absorbing it, so exposed faces dry relatively quickly.
Recommendations
3
- Visually inspect routes for dampness on arrival — focus on seepage lines on the north crag and shaded recesses; plan to climb in the afternoon when the west-facing rock has had direct sun.
- Favour the main south-facing or well-exposed sections of the crag over the north crag, where seepage is most persistent.
- Check the BMC RAD for any active peregrine nesting restrictions before visiting.
Do Not Climb
40%
59 days ago
Castle Rock has received nearly 50mm of rain in the past week, including a very heavy 21.7mm event on August 19th and 12.7mm on August 20th, with only one full dry day (today) since. While rhyolite dries relatively quickly on the surface, the W/NW aspect, high ambient humidity (91% average over the last week), and known seepage lines on the north crag mean conditions are very likely still damp in places.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's persistent seepage lines will almost certainly still be running after 34mm of rain fell on August 19-20, even though the surface rock elsewhere may appear dry.
- The W/NW aspect means the crag receives no direct sun until the afternoon, so morning visits will find slower drying — particularly problematic given the recent saturated conditions.
- Castle Rock has a serious mountain atmosphere at 300m with long routes; a slip on damp friction-dependent BVS rock at this grade (E1-E2 classics) carries significant consequence.
- Peregrine nesting restrictions should be checked before visiting, though these typically ease by late summer.
Warnings
2
- Seepage lines on the north crag are very likely still active after 34mm of rain fell over Aug 19-20; routes crossing these lines will be dangerously slippery.
- Friction-dependent BVS routes at E1-E2 grades carry high consequence if surfaces are even slightly damp — do not rely on surface appearance alone.
Reasoning
With 47.4mm in the last 7 days including heavy falls on Aug 19-20, and only one dry day since, surface moisture is likely cleared on exposed faces but seepage and sheltered areas will remain damp.
Moderate westerly winds (~13-17 km/h) have aided surface drying today, but the NW aspect limits sun exposure to afternoons only, and average humidity of 91% over the past week severely hampers evaporation.
Borrowdale Volcanic Series rhyolite is non-porous and suffers no structural damage when wet; the risk is entirely friction-related.
Late August offers reasonable daylight hours and temperatures, but the recent cool, wet spell (averaging only 10.4°C over the past week) has suppressed drying conditions well below summer norms.
Contributing Factors
7
47.4mm in the last 7 days, including a very heavy 21.7mm day on Aug 19 and 12.7mm on Aug 20, has saturated the ground and fed seepage lines.
Just a single full dry day (today, Aug 22) since the heavy rain is insufficient to clear seepage lines and sheltered damp patches on this aspect.
Average humidity of 91% over the past week dramatically slows evaporation even where the rock surface is wind-exposed.
The W/NW facing crag only receives direct afternoon sun, meaning morning and early afternoon conditions will be slowest to dry.
Winds of 13-22 km/h today and tomorrow provide some surface drying, though partially sheltered exposure limits the effect.
BVS rhyolite does not absorb water, so surface drying is possible within hours on exposed faces once humidity drops.
The next few days show minimal precipitation and humidity dropping to 72% on Aug 24, which should steadily improve conditions.
Recommendations
3
- Wait at least until August 24 when humidity drops to 72% and a second consecutive dry day will have allowed seepage lines to diminish significantly.
- If visiting sooner, inspect the north crag seepage lines and any shaded recesses carefully before committing — retreat from steep E1/E2 routes on damp rock is serious.
- Prioritise afternoon sessions to maximise the benefit of direct westerly sun on the crag face.
Do Not Climb
35%
60 days ago
Castle Rock has received nearly 50mm of rain in the last 7 days, including a very heavy 21.7mm on August 19th and 12.7mm on the 20th, with a further 2mm today. Although the forecast shows a drying window from tomorrow, the crag's W/NW aspect and persistent seepage lines on the North Crag mean reliable drying has not yet begun — we recommend waiting at least until tomorrow afternoon before considering climbing.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The North Crag's seepage lines are likely running heavily after 34mm fell on Aug 19–20, and these can persist for 24–48 hours even on non-porous rock.
- The W/NW aspect means the crag receives no direct sun until the afternoon, so morning visits will find lingering surface moisture even after dry overnight conditions.
- Check for peregrine nesting restrictions before visiting — spring restrictions may still be in effect into August in some years; consult the BMC RAD for current status.
- The NE wind today is blowing onto the sheltered side of this W/NW-facing crag, providing minimal drying benefit; the forecast switch to W winds from tomorrow will be more effective.
Warnings
2
- Friction on BVS rock is drastically reduced when damp — falls on apparently 'nearly dry' rock are a real risk on the steep routes here.
- Seepage lines on the North Crag may remain wet for days after heavy rain; do not assume the entire crag is dry because one section appears so.
Reasoning
With 21.7mm on the 19th, 12.7mm on the 20th, and 2mm today, the rock surface and seepage lines are almost certainly still wet, especially on the North Crag and in any recessed or sheltered features.
Today's NE wind offers poor drying for a W/NW-facing crag, and humidity remains at 85%; meaningful drying will only begin tomorrow when winds shift westerly and precipitation ceases.
Borrowdale Volcanic rhyolite is non-porous and suffers no structural damage from moisture — the risk is purely friction loss on damp surfaces.
Mid-to-late August in the Lake District is well within the climbing season, but the recent spell of wet, cool weather (averaging only 10.5°C over the past week) has suppressed drying significantly.
Contributing Factors
7
Over 34mm fell on August 19–20 alone, with a further 2mm today, saturating the crag surface and feeding seepage lines.
Zero consecutive dry days to date means no sustained drying period has begun.
Average humidity of 91% over the past week severely limits evaporation from rock surfaces.
Today's NE wind blows onto the sheltered lee side of this W/NW-facing crag, providing minimal surface drying.
Two to three completely dry days are forecast from August 22nd with dropping humidity and westerly winds, which should progressively dry the crag.
BVS rhyolite does not absorb water, so surface drying can be rapid once conditions allow — no extended internal drying period required.
Temperatures averaging only 10.5°C over the past week limit evaporation rates even when wind is present.
Recommendations
3
- Wait until at least the afternoon of August 22nd to allow westerly winds and dropping humidity to begin drying the surface, then visually assess conditions on arrival.
- Avoid the North Crag seepage lines for at least 48 hours after the last rain — focus on more exposed, well-drained sections of the South Crag first.
- Check the BMC RAD for any active peregrine nesting restrictions before planning your visit.
Do Not Climb
85%
61 days ago
Castle Rock of Triermain is currently wet and unsuitable for climbing. Heavy rain yesterday (21.4mm) followed by further showers today (4.7mm forecast total) means the rock will be saturated, with seepage lines active and friction severely compromised on the BVS rock.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag seepage lines will be running heavily after 21.4mm yesterday plus ongoing rain today, and these can persist for 24–48 hours even after rain stops.
- The W/NW aspect means the crag will not receive direct sun until afternoon, and with 100% cloud cover forecast through midday today, no solar drying will occur.
- The NE wind direction today is unusual and means the crag's west-facing surfaces are somewhat sheltered from wind-assisted drying.
- Check for peregrine nesting restrictions before visiting — spring restrictions can occasionally extend into summer if late broods are present.
Warnings
2
- Active seepage lines on the north crag present a serious slip hazard on steep routes like North Crag Eliminate.
- The approach path will be wet and slippery — take care even if not climbing.
Reasoning
The rock is currently wet: 21.4mm fell yesterday, with intermittent showers continuing through this morning (100% humidity, 100% cloud), leaving surfaces saturated and seepage lines fully active.
Minimal drying has occurred — the NE wind shelters the W/NW-facing crag, humidity has been at or near 100% all morning, and no sun has reached the rock; even the brief afternoon drying window (14:00–17:00) with reduced humidity is insufficient to dry the accumulated moisture.
BVS rhyolite is non-porous and not at risk of structural damage from moisture, but friction loss on wet volcanic rock is severe and makes steep routes like Overhanging Bastion dangerously slippery.
Mid-August should offer reasonable drying potential, but the recent week has been exceptionally wet (36.9mm in 7 days) with persistently high humidity averaging 91%, limiting any meaningful drying between showers.
Contributing Factors
6
21.4mm fell yesterday and 4.7mm today, on top of 36.9mm in the past week, leaving the crag thoroughly saturated.
Humidity has averaged 91% over the past seven days and has been at 99–100% through today's morning hours, preventing evaporative drying.
Intermittent rain is forecast through midday with a further 0.6mm possible this evening, continually rewetting any surfaces that begin to dry.
Today's NE wind direction means the west-facing crag is largely sheltered, reducing wind-assisted drying of the rock surface.
A 3–4 hour dry window from 14:00–17:00 with humidity dropping to 69% is too short to dry a saturated crag with active seepage.
BVS rhyolite does not absorb water, so once rain stops and conditions improve, the surface can dry relatively quickly compared to sandstone.
Recommendations
3
- Do not climb today — the crag is wet with active seepage and dangerously reduced friction on the steep routes.
- Consider visiting from August 22nd onwards when two consecutive dry days with lower humidity should allow the rock to dry adequately.
- If visiting on the 22nd or 23rd, check seepage lines on the north crag in person before committing to routes — these can linger after prolonged wet spells.
Do Not Climb
92%
63 days ago
Castle Rock of Triermain is currently wet and receiving intermittent rain throughout the day with 100% cloud cover and near-saturation humidity; conditions are clearly unsuitable for climbing today. The forecast shows continued rain tomorrow and the next day, with a potential drying window emerging from August 21st onwards.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines will be running persistently given the 59mm of rain over the past 28 days and ongoing precipitation — these can take a full dry day or more to stop weeping even after rain ceases.
- The W/NW aspect means the crag is sheltered from the current southerly and south-westerly winds, reducing effective drying — the forecast shift to northerly winds on August 21st will blow directly onto the face and aid drying significantly.
- At 300m with 100% cloud cover today and tomorrow, the crag is likely sitting in low cloud or mist, adding ambient moisture on top of direct rainfall.
- Peregrine nesting restrictions should be checked before visiting — although the main spring season has passed, late-season disturbance policies may still be in effect at some Lake District crags.
Warnings
2
- Wet BVS rock is extremely slippery — the steep routes at Castle Rock (E1–E2+) rely heavily on friction and are dangerous when damp.
- The crag may be in low cloud at 300m given current conditions, reducing visibility on the approach and adding ambient moisture.
Reasoning
The rock is currently wet from intermittent rain throughout today (6.6mm total), with humidity at 93–100% all day and no dry window.
Despite moderate westerly winds (~27–31 km/h), the W/NW aspect means these winds do not blow directly onto the face, and with continuous cloud and near-saturation humidity there is effectively zero drying taking place.
BVS rhyolite is non-porous so there is no structural damage risk, but the slippery wet surface makes climbing dangerous — friction on these steep routes is essential for safety.
Mid-August should offer reasonable conditions but the current spell is unusually wet and cool for summer, with temperatures 5–8°C below seasonal norms and persistent frontal systems.
Contributing Factors
6
Intermittent rain totalling 6.6mm throughout the day with no sustained dry window means the rock surface is continuously wet.
Humidity at 93–100% all day prevents any evaporative drying even between rain showers.
100% cloud cover all day eliminates solar heating that would otherwise help dry the west-facing rock in the afternoon.
Winds of 25–31 km/h are present but blow from the west onto a W/NW-facing crag — helpful for drying in principle, but negated by continuous moisture input and saturated air.
Nearly 60mm over 28 days with frequent rain events means seepage lines on the north crag will be well-charged and slow to dry.
Temperatures of 10–13°C at crag level are well below summer norms, slowing evaporation rates.
Recommendations
3
- Do not climb today — the crag is wet with ongoing rain and no usable window.
- The earliest realistic opportunity is August 21st after two forecast dry days; check seepage lines on the north crag before committing to routes there.
- Monitor conditions closely from August 21st — if the dry spell holds, the south crag and less seepage-prone routes should come into condition first.
Do Not Climb
90%
64 days ago
Castle Rock of Triermain is currently wet and will remain so today, with intermittent drizzle throughout the day, near-saturated humidity, 100% cloud cover, and heavy rain forecast this evening. The next five days bring continued heavy rainfall with no realistic drying window until August 22 at the earliest.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The W/NW aspect means the crag is fully exposed to the prevailing SW–W rain-bearing systems that have dominated the last three weeks, receiving the brunt of each shower.
- Known seepage lines on the North Crag will be actively running given the persistent wet spell — nearly 58mm in the last 28 days with further heavy rain forecast.
- Light winds today (under 15 km/h until evening) combined with near-100% humidity mean virtually no evaporative drying is occurring on the rock surface.
- Check for peregrine nesting restrictions before any future visit; though the main spring restriction period is likely over by mid-August, local notices should be confirmed.
Warnings
3
- Heavy rain of 21mm is forecast for August 20, which will fully saturate all seepage lines and drainage features on the crag.
- Friction on BVS rhyolite is dramatically reduced when damp — the steep, technical nature of Castle Rock routes makes slips very likely on wet rock.
- 100% cloud cover at 300m altitude means the crag may be in or near cloud today, reducing visibility and adding condensation moisture.
Reasoning
The rock is currently wet: 1.6mm fell yesterday, light drizzle has fallen overnight and through this morning, and humidity has been at 95–99% all day with no drying opportunity.
With 100% cloud cover, near-saturated humidity, and light winds under 15 km/h, there is effectively zero evaporative drying happening today — the W/NW aspect receives no sun through the overcast and the air itself is too moisture-laden to wick water off the surface.
BVS rhyolite is non-porous and faces no structural damage risk from moisture, but the friction-dependent nature of the classic routes (steep, technical) makes damp surfaces genuinely dangerous.
Mid-August should offer reasonable conditions but this is an unusually wet and cool spell for summer; temperatures are well below seasonal norms and persistent frontal systems are keeping the crag saturated.
Contributing Factors
6
Intermittent drizzle throughout the day with 8.2mm total forecast, culminating in heavy rain (6.6mm) this evening — the rock will not dry at any point today.
Humidity has been 92–99% all day with 100% cloud cover, preventing any meaningful evaporative drying even during brief dry spells.
Nearly 10mm in the last 7 days and 58mm over 28 days means seepage lines and drainage features on the crag are fully charged.
Winds are only 3–11 km/h through the afternoon, far too light to assist surface drying on a sheltered crag at 95%+ humidity.
BVS rhyolite will not suffer structural damage and will dry relatively quickly once a genuine dry, breezy window arrives.
21.2mm forecast on Aug 20 alone, with 37.8mm total over the next 6 days — conditions will worsen before they improve.
Recommendations
3
- Do not visit Castle Rock today or over the next three days; the crag will be wet and dangerous.
- Monitor the forecast for August 22 onwards — the first potential dry window, though conditions will need on-site assessment after the heavy rain on the 20th.
- If visiting the Lakes this week, consider indoor climbing walls in Keswick or Ambleside as alternatives.
Do Not Climb
72%
65 days ago
Today has seen 1.5mm of rain with very high humidity (92%), and the forecast shows a significant wet spell arriving over the next three days with over 28mm expected. While the rock had a promising dry spell from Aug 10–15, today's rain and the incoming front mean conditions are deteriorating and the crag is unlikely to offer reliable friction.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The west/NW-facing aspect means Castle Rock catches afternoon sun but misses morning drying — on days like today with high humidity and light rain, surfaces can remain damp well into the afternoon.
- Known seepage lines on the North Crag persist after prolonged wet spells; the cumulative rain from late July through early August (~49mm in 28 days) means these may still be active even after the recent dry window.
- Peregrine nesting restrictions should be checked before visiting — although the main restriction season is typically March–June, late-season nesting is possible and the BMC RAD should be consulted.
- The crag's 300m altitude and sheltered valley position between Blencathra and Helvellyn can trap cloud and moisture, keeping humidity high even when lower valleys appear drier.
Warnings
2
- Friction on BVS rock is dramatically reduced when damp — do not be deceived by surfaces that appear dry but retain a moisture film in high humidity.
- Heavy rain forecast (13.7mm) on August 19th may cause localised flooding on the approach path through St John's in the Vale.
Reasoning
Today's 1.5mm rain combined with 92% humidity means rock surfaces are currently damp, negating the benefit of the preceding 5-day dry spell (Aug 10–15).
Light SW winds at 16 km/h and the W/NW aspect provide limited drying potential today, and with humidity above 90% evaporation will be negligible — surfaces will not dry meaningfully before the next rain arrives tomorrow.
Borrowdale Volcanic Series rhyolite is non-porous and faces no structural risk from moisture; the concern is purely friction loss on wet or damp surfaces.
Mid-August in the Lake District is within the main climbing season but Atlantic weather systems bring frequent frontal rain, and the current pattern shows a classic westerly wet spell establishing itself.
Contributing Factors
6
1.5mm precipitation today with 92% humidity means rock surfaces are currently damp and unlikely to dry.
4.6mm tomorrow, 10.3mm on the 18th, and 13.7mm on the 19th will keep the crag thoroughly wet for at least three more days.
Five consecutive dry days (Aug 10–15) with warm temperatures would have dried surface moisture well, but today's rain has reset conditions.
The W/NW aspect normally aids afternoon drying, but persistent cloud cover and high humidity over the coming days will largely negate this benefit.
Winds of 22–29 km/h forecast over the next few days will aid surface drying during any dry interludes, though sustained rain will overwhelm this.
The North Crag's seepage lines are likely to reactivate with the incoming heavy rain after the already-damp late July period.
Recommendations
3
- Wait for the wet spell to pass — conditions are unlikely to be suitable before August 21st at the earliest.
- If visiting on August 21st after the forecast clears, check seepage lines on the North Crag carefully before committing to routes there.
- Consider the South Crag and main buttress routes that catch afternoon sun as these will dry fastest once the rain stops.
Likely Safe to Climb
82%
66 days ago
Castle Rock has had six consecutive dry days with improving temperatures and moderate winds, which is more than sufficient to dry non-porous Borrowdale Volcanic rock. Today looks like a good window before a deteriorating forecast brings significant rain from tomorrow onwards.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's persistent seepage lines may still be slightly damp after the wet spell earlier in the month (nearly 10mm on Aug 4–5), though six dry days should have cleared most surface moisture.
- The W/NW aspect means the crag catches afternoon sun, so conditions will be better in the afternoon than early morning — plan to climb from midday onwards for best friction.
- Peregrine nesting restrictions can apply in spring; check the BMC RAD before visiting, though restrictions are unlikely in mid-August.
- A significant wet spell is forecast from Aug 17–20 (over 35mm expected), so today may be the last good climbing window for nearly a week.
Warnings
1
- Significant deterioration forecast from Aug 17–20 with heavy rain and strong winds; do not plan multi-day trips without contingency.
Reasoning
Six consecutive dry days, including three warm days (Aug 11–13 reaching 19–24°C) with moderate-to-strong southerly winds, will have thoroughly dried the non-porous volcanic rock surface.
Persistent W and S winds at 20–32 km/h over the dry spell, combined with the W/NW aspect catching afternoon sun, provide excellent drying conditions for a rock type that sheds surface moisture within hours.
Borrowdale Volcanic Series rhyolite is non-porous and extremely hard; there is no structural risk from the preceding wet period.
Mid-August is peak summer season with long daylight hours and no freeze-thaw concerns; the recent warm spell (22–24°C on Aug 12–13) is favourable despite today's cooler 13°C.
Contributing Factors
5
No precipitation since Aug 9, giving non-porous rock ample time to shed all surface moisture.
Temperatures of 19–24°C on Aug 11–13 with strong southerly winds significantly accelerated evaporation of any residual moisture.
Westerly wind at 18 km/h helps maintain dry surfaces on this partially exposed W/NW-facing crag.
Humidity at 84% and a cooler max of 13°C mean conditions are not ideal, though the rock should remain dry from the preceding dry spell.
Over 35mm of rain is forecast from Aug 16–20, making today potentially the last good window for several days.
Recommendations
3
- Climb today if possible — this is likely the last dry window before a prolonged wet spell arriving tomorrow.
- Favour afternoon sessions to take advantage of the W/NW aspect catching direct sun and maximising friction.
- Avoid known seepage lines on the north crag if any residual dampness is visible; stick to the well-drained main buttress routes.
Climbing Outlook