Condition Analysis
AI-powered assessment using site data and 14-day weather history
Today is dry with a useful afternoon window where humidity drops into the 60s, and the non-porous dolerite should be surface-dry after yesterday's dry spell — but the north-facing aspect, 100% cloud cover, and high overnight humidity mean residual dampness or condensation is possible. A significant wet spell begins tomorrow with over 60mm forecast in the next five days, so today is the last realistic climbing opportunity for nearly a week.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect at 260m means this crag rarely receives direct sun, so surface moisture from condensation and seepage can linger even when the rock itself doesn't absorb water.
- Crag Lough sits on the exposed Whin Sill ridge and today's easterly wind (~20 km/h) will blow directly onto the north face, aiding surface drying through the afternoon.
- Peregrine falcons nest here in spring — by late August nesting restrictions should have lifted, but check BMC RAD for current status before visiting.
- Vegetation and boggy ground above the crag on the Hadrian's Wall escarpment can channel seepage down certain lines for days after heavy rain, even though the dolerite itself is non-porous.
Warnings
2
- Dolerite is extremely slippery when damp — a thin film of moisture invisible to the eye can drastically reduce friction; test holds carefully.
- Heavy rain (24mm+) is forecast from tomorrow; do not plan multi-day trips to this crag this week.
Reasoning
The last measurable rain was 2.1mm on August 25th, with today fully dry; the non-porous dolerite surface should be largely dry by afternoon, though overnight humidity of 95–98% may leave condensation films on the north-facing rock.
A steady easterly wind of ~17–23 km/h and afternoon humidity dropping to 61–65% should effectively strip surface moisture from the exposed face through the midday-to-evening window.
Dolerite does not weaken when wet so hold breakage from moisture is not a concern, though loose blocks at the crag base remain a perennial hazard from freeze-thaw weathering.
Late August offers reasonable daylight hours and no freeze-thaw risk; the recent wet pattern (65mm in 28 days) and incoming frontal system are typical of late-summer Northumberland weather.
Contributing Factors
6
Whin Sill dolerite does not absorb moisture, so structural damage from climbing on damp rock is not a concern — the issue is purely surface friction.
No precipitation today and humidity drops to ~61% by midday with moderate wind, creating a viable afternoon climbing window before tomorrow's heavy rain.
The north face receives no direct sun and overnight humidity reached 98%, so condensation or residual dampness may persist on shaded sections well into the morning.
Over 60mm of rain is forecast from August 27–31, making today the last realistic opportunity before a prolonged wet spell.
The crag's exposed position on the Whin Sill escarpment means the ~20 km/h easterly wind will accelerate surface evaporation through the afternoon.
Average humidity over the past week has been 82%, and overnight readings have been consistently above 90%, which sustains surface dampness on north-facing rock.
Recommendations
3
- Target the afternoon window between 11:00 and 18:00 today when humidity is lowest (61–69%) and wind is drying the face — this is your best and likely last window before a multi-day wet spell.
- Physically touch the rock before committing to any route; dolerite becomes treacherously slippery with even a thin moisture film, so if any dampness is felt, back off.
- Avoid routes with known seepage lines from the grassy escarpment above, as recent rain (15.6mm on Aug 19, plus smaller amounts since) may still be feeding drainage channels.
Previous Analyses
Likely Safe to Climb
85%
57 days ago
Crag Lough has had four consecutive dry days following rain on August 20th, and today is forecast to remain completely dry with humidity dropping to around 50% by early afternoon. The non-porous dolerite will be well dried by now, and conditions through midday to late afternoon look excellent for climbing.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect means the crag receives virtually no direct sunlight, so any seepage from the grassy top or damp vegetation above can linger in shaded corners even after the main face has dried.
- Crag Lough sits on the Whin Sill escarpment at 260m and is fully exposed to prevailing westerly winds, which is the primary drying mechanism given the lack of direct sun.
- Peregrine falcons nest here in spring — by late August nesting restrictions should be lifted, but check the BMC RAD for current status before climbing.
- The crag base sits above a lough and loose blocks from active freeze-thaw accumulate at the bottom; though freeze-thaw is not a summer concern, rockfall hazard from stacked debris remains.
Warnings
1
- Rain is forecast from tomorrow (Aug 25) through August 29 with a cumulative total of ~31mm — plan today as your primary climbing window.
Reasoning
Four full dry days since the last significant rain (15.6mm on Aug 19, 4.1mm on Aug 20), combined with moderate winds and exposed position, means the non-porous dolerite surface should be thoroughly dry.
Despite the north-facing aspect limiting solar input, consistent winds of 13–19 km/h over the dry spell and the rock's non-porous nature mean surface moisture will have evaporated well within the first day after rain.
Dolerite does not absorb water so there is no structural weakening concern; the main hazard is inherently loose blocks at the crag base, which is a year-round feature of Whin Sill crags.
Late August offers long daylight hours and no freeze-thaw risk; summer conditions are near-optimal for this venue, though the recent wet spell and high average humidity (83% over the last week) are typical of the Northumberland uplands.
Contributing Factors
5
No measurable precipitation since August 20th gives ample drying time for non-porous dolerite, which typically dries within hours.
Humidity drops to ~49% by mid-afternoon with moderate easterly winds, providing excellent friction conditions on the dense rock.
The fully exposed Whin Sill escarpment benefits from consistent wind, which is the dominant drying mechanism for this north-facing crag.
The northerly aspect means essentially no direct sun reaches the face, so any sheltered seepage patches or vegetation-fed damp spots dry more slowly than on a sunlit crag.
3.5mm forecast for August 25th marks the start of a prolonged unsettled spell, so today may be the last good climbing window for several days.
Recommendations
3
- Climb today between late morning and late afternoon when humidity is lowest (49–53%) for best friction on the dense dolerite.
- Inspect the crag base carefully for loose blocks and recent rockfall debris before setting up belays.
- Be aware that rain returns tomorrow — this is likely the last reliable dry window until at least August 30th.
Marginal — Assess Conditions
72%
58 days ago
Three consecutive dry days with moderate westerly winds should have dried the non-porous dolerite surface, but high average humidity (86%) and the north-facing aspect mean residual dampness in sheltered corners and seepage lines is possible. Climbers should visually check holds before committing, especially on lower-angled slabs where friction matters most.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect receives virtually no direct sun even in August, so drying relies almost entirely on wind exposure — the exposed ridgeline position helps significantly but shaded recesses can remain damp.
- Seepage from the grassy hilltop above (Hadrian's Wall path and grazing land) can persist for days after heavy rain, creating weeping bands even when the main rock face appears dry.
- Peregrine falcons nest here in spring — by late August nesting restrictions should be lifted, but check current BMC RAD notices before visiting.
- The crag sits on a UNESCO World Heritage Site; access is permissive and climbers should avoid disturbing the Wall remains or creating new paths to maintain goodwill.
Warnings
2
- Loose blocks at the crag base from freeze-thaw weathering are a persistent hazard — helmets essential and beware of stacking belayers below the cliff.
- Seepage bands from the grassy hillside above may persist even when the main face appears dry — test for wet streaks before trusting smears.
Reasoning
The dolerite surface should be largely dry after three rain-free days, but 15.6mm on Aug 19 followed by 4.1mm on Aug 20 was a significant soaking, and persistent high humidity (84–88%) has slowed evaporation.
Moderate westerly winds (13–19 km/h) over the exposed ridge have provided effective surface drying, though the north-facing aspect contributes no solar heating and the east-facing wind today (10.8 km/h) is lighter than recent days.
Whin Sill dolerite does not weaken when wet, but loose blocks at the crag base from freeze-thaw weathering remain a year-round hazard requiring care on approach and belaying.
Late August offers reasonable drying conditions and long daylight hours, though the recent unsettled spell with 30mm in the past week is typical of the transition toward autumn weather patterns.
Contributing Factors
6
No measurable rain since Aug 20 (4.1mm), giving the non-porous surface ample time to shed standing water.
Average humidity over the past week is 86%, which slows evaporation and can leave a thin moisture film on the dense black rock.
The north aspect receives negligible direct sunlight even in summer, so drying depends almost entirely on wind rather than solar heating.
The high exposed position on the Whin Sill escarpment ensures consistent airflow that strips surface moisture effectively.
15.6mm fell on Aug 19 and 4.1mm on Aug 20, which may still be feeding seepage from the grassy ground above the crag.
Dolerite absorbs almost no water, so the rock itself does not retain internal moisture — only surface dampness and seepage are concerns.
Recommendations
3
- Visually inspect holds and test friction on a low-consequence section before committing to harder routes — the dense black rock gives little visual cue when damp.
- Avoid lower-angled slab routes where friction is critical; steeper faces with positive holds will be more forgiving if residual moisture persists.
- Check the BMC RAD for any remaining peregrine nesting restrictions and verify current access arrangements for the Hadrian's Wall corridor.
Marginal — Assess Conditions
70%
59 days ago
After a very wet spell peaking on Aug 19 (15.6mm), two dry days with moderate westerly winds should have dried the non-porous dolerite surface. However, persistent high humidity (80–88%) and the north-facing aspect mean seepage and residual dampness in cracks and sheltered areas are likely — a visual check on arrival is strongly recommended.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect receives virtually no direct sun even in summer, so drainage seepage from the grassy top and crack systems can persist long after surface rock appears dry.
- Crag Lough sits on the exposed Whin Sill ridge at 260m, so wind-driven drying is effective on open faces, but recessed buttresses and corners will lag behind.
- Peregrine falcons nest here in spring — by late August restrictions are typically lifted, but check the BMC RAD for any residual closures on specific buttresses.
- The crag sits within the Hadrian's Wall UNESCO World Heritage corridor — respect access restrictions and avoid disturbing archaeological features at the crag base.
Warnings
2
- Dolerite is exceptionally slippery when damp — a surface that looks dry can still have an invisible moisture film; test friction before committing.
- Seepage from the grassy crag top may persist on some lines despite dry weather; retreat if water is visible running down the face.
Reasoning
The dolerite surface should be largely dry after two rain-free days, but 32mm fell in the preceding seven days (including 15.6mm on Aug 19 and 4.1mm on Aug 20), and persistent 84–92% humidity will have slowed evaporation of pooled and seepage water.
Moderate westerly winds (13–19 km/h) on an exposed ridge aid surface drying considerably, but the north-facing aspect denies any solar heating, leaving sheltered corners, cracks, and seepage bands slower to dry.
Whin Sill dolerite does not weaken when wet; the primary risk is from pre-existing loose blocks and active freeze-thaw debris at the crag base, though freeze-thaw is not a concern in August.
Late summer offers reasonable drying potential even at this altitude, but the recent run of Atlantic fronts has kept humidity stubbornly high and temperatures below seasonal average, limiting drying efficiency.
Contributing Factors
6
15.6mm on Aug 19 and 4.1mm on Aug 20 left significant surface water and seepage just two days ago.
Whin Sill dolerite does not absorb moisture, so surface water clears far faster than on sandstone or gritstone.
No precipitation on Aug 21–22 has allowed exposed faces to shed surface water.
Average humidity has been around 84–88% over the past week, significantly slowing evaporation of seepage and pooled water.
No direct sunlight reaches the crag face, removing the most effective drying mechanism for seepage bands and damp recesses.
Moderate westerly winds at 13–20 km/h across the open Whin Sill ridge promote effective wind-driven surface drying.
Recommendations
3
- Visually inspect the rock surface on arrival — open, wind-exposed buttresses are most likely to be dry; avoid recessed corners and seepage-streaked sections.
- Carry a towel and test friction on lower holds before committing to harder routes, as dolerite becomes extremely slippery with even a thin moisture film.
- Check the BMC RAD for any residual peregrine nesting restrictions and confirm Hadrian's Wall access conditions before travelling.
Marginal — Assess Conditions
62%
60 days ago
The crag has had a very wet week (32mm in 7 days) with significant rain on Aug 19 (15.6mm) and Aug 20 (4.1mm), but today is nearly dry and the forecast shows a promising dry window from tomorrow through Aug 25. Being non-porous dolerite, the rock surface itself should dry within hours of rain stopping, but the north-facing aspect, high humidity (84–88%), and seepage from saturated ground above mean dampness may linger in places.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect receives virtually no direct sun in any season, so surface drying relies almost entirely on wind and ambient temperature — check for persistent damp films on the black rock.
- Heavy recent rainfall (32mm in 7 days) will have saturated the peaty ground above the crag, and seepage lines from Hadrian's Wall ridge grassland can weep for days after prolonged wet spells even though the dolerite itself doesn't absorb water.
- Loose blocks at the base are a perennial hazard on the Whin Sill; recent heavy rain and freeze-thaw cycles over winter may have loosened additional material — test holds carefully.
- Peregrine falcons nest here in spring; by late August restrictions should have lifted, but check the BMC RAD for any extended closures before visiting.
Warnings
2
- Dolerite is extremely slippery when wet — even a thin moisture film invisible to the eye can dramatically reduce friction; test the surface before committing to any route.
- Loose blocks at the crag base are a serious hazard; recent heavy rain may have undermined block foundations — helmet mandatory and careful foot placement on approach.
Reasoning
The rock surface is likely still damp today given 4.1mm fell yesterday (Aug 20) and only a trace today, combined with persistent 84–88% humidity and a north-facing aspect that receives no direct sun.
Moderate winds (15–19 km/h) from the north today will help surface drying on this exposed ridge, and with a dry forecast from tomorrow the non-porous dolerite surface should be dry by tomorrow morning, though seepage from saturated ground above may persist.
Dolerite does not weaken when wet, but loose blocks at the crag base are a year-round hazard exacerbated by the recent prolonged wet period saturating soil around block foundations.
Late August offers reasonable daylight hours and no freeze-thaw risk, but this has been an unusually wet and cool spell for summer with temperatures well below seasonal norms.
Contributing Factors
6
32mm in 7 days including 15.6mm on Aug 19 and 4.1mm on Aug 20 means the ground is thoroughly saturated, feeding seepage onto the crag face.
Whin Sill dolerite does not absorb moisture and can dry within hours of rain stopping, unlike sandstone which requires days.
The crag receives no direct sunlight, so drying depends entirely on wind and ambient temperature, slowing surface moisture evaporation significantly.
The high, exposed position on the Whin Sill ridge ensures consistent airflow that compensates somewhat for the lack of sun, aiding surface drying.
Humidity has averaged 88% over the past week and is 84% today, which significantly slows evaporation and may leave a thin moisture film on the dense black rock.
No rain is forecast from Aug 22–25, giving four full dry days for the surface and seepage lines to dry before the next significant rain on Aug 26.
Recommendations
3
- Wait until tomorrow (Aug 22) to allow a full dry day with lower humidity (74%) and moderate wind to clear residual surface moisture from the recent wet spell.
- On arrival, run your hand across the rock surface — dolerite becomes glass-like when even slightly damp, so if the black rock has any sheen or feels slick, back off.
- Avoid routes with obvious seepage lines or drainage gullies, as saturated ground above the crag will continue to weep for several days despite the dry forecast.
Do Not Climb
45%
61 days ago
Crag Lough has experienced a very wet spell with 32mm in the last 7 days including 16mm yesterday and 3.5mm today, and the north-facing dolerite will still be wet or damp through most of today despite the afternoon drying window. Conditions should improve markedly from tomorrow afternoon through the 22nd–23rd if the dry forecast holds.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect means the crag receives virtually no direct sun, so drying relies entirely on wind and ambient temperature — even in summer, surface moisture lingers longer here than at south-facing venues.
- Seepage from the grassy top of the Whin Sill escarpment and the lough below creates persistent damp bands on the cliff face for days after sustained rain, even though the dolerite itself is non-porous.
- Peregrine falcons nest on these buttresses in spring; by mid-August restrictions should be lifted, but climbers should check the BMC RAD for any late-season extensions.
- The crag sits on the exposed Hadrian's Wall ridge at 260m and is a UNESCO World Heritage Site — avoid disturbing loose blocks at the base, and be mindful of Heritage Site sensitivities regarding fixed gear and impact.
Warnings
2
- Dolerite becomes extremely slippery when wet — even a thin moisture film can cause unexpected slips on what are normally secure holds.
- Seepage from saturated ground above the crag may persist for 2–3 days after this wet spell, creating wet bands even when the main face appears dry.
Reasoning
With 16mm yesterday, 2mm on the 18th, and 3.5mm today (mostly before 10am), the rock surface is currently wet; the afternoon clearing window (humidity dropping to ~59% by 15:00) may begin surface drying but is insufficient to fully dry the face given the north aspect.
Moderate westerly-to-NE winds (~20 km/h) on this exposed ridge will help strip surface moisture from the non-porous dolerite, but the north-facing orientation and persistent high humidity (85% daily average) limit evaporative drying significantly.
Dolerite does not weaken when wet, so hold breakage from moisture is not a concern; however, active freeze-thaw loosens blocks at the crag base — not currently relevant in August but loose blocks remain a year-round hazard.
Mid-August offers reasonable daylight hours and no freeze-thaw risk, but the recent pattern of frequent Atlantic fronts has kept humidity very high (88% average over 7 days), slowing drying despite summer temperatures.
Contributing Factors
6
16.1mm fell yesterday with an additional 3.5mm today, leaving the rock surface wet through the morning.
No direct sun reaches the face, so drying depends entirely on wind and ambient conditions, which is a significant disadvantage.
The high exposed position on the Whin Sill ridge means moderate winds (~14–20 km/h) will help strip surface moisture from the non-porous rock.
Whinstone does not absorb water, so only surface moisture and seepage need to clear — no structural damage risk from climbing damp rock.
Humidity has averaged 88% over the past week and remains 85% today, significantly slowing evaporation and surface drying.
Humidity is forecast to drop to 59–66% between 13:00–15:00 with clearing skies, offering a partial drying window for the surface.
Recommendations
3
- Wait until tomorrow afternoon (Aug 21) at the earliest, when the morning trace rain should have cleared and winds will have had time to dry the non-porous surface.
- The best window this week looks to be August 22–23 with zero forecast precipitation, lower humidity (76–77%), and moderate winds — aim for these days.
- On arrival, run your hand across the rock surface and test friction on a low hold before committing to any route; dolerite is treacherously slippery with even a thin moisture film.
Do Not Climb
45%
62 days ago
Crag Lough has received nearly 4mm of rain today with persistent high humidity and cloud cover; the dolerite surface is very likely still damp and slippery. Although the rock is non-porous and dries quickly in favourable conditions, the north-facing aspect, 100% cloud cover, and humidity above 80% for most of the day severely limit drying.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect receives virtually no direct sun in any season, so drying relies almost entirely on wind — and today's wind has been moderate at best (7–20 km/h).
- Crag Lough sits atop the Whin Sill escarpment at 260m where cloud and mist frequently engulf the crag, maintaining a moisture film even when rain has stopped.
- Peregrine falcons nest here in spring — check BMC RAD for any lingering seasonal restrictions, though by mid-August these should be lifted.
- The crag base is prone to loose blocks from freeze-thaw; while not a winter concern today, the boggy approach and wet grass on the escarpment slope add risk in these damp conditions.
Warnings
2
- Dolerite is extremely slippery when damp — a thin moisture film that is hard to see can cause sudden foot slips on lower-angled terrain.
- The grassy escarpment approach will be very slippery after recent rain; take care on the descent to the crag base.
Reasoning
Rain fell through the early hours and intermittently until mid-morning, with humidity above 90% for most of the day; the rock surface is very likely still carrying a moisture film.
Despite being an exposed site, the north-facing aspect receives no direct sun and today's moderate westerly wind (10–20 km/h) combined with persistent cloud cover and high humidity means drying has been minimal.
Dolerite does not suffer structural weakening when wet, so hold breakage from moisture is not a concern — the risk is purely frictional.
Mid-August should offer reasonable drying conditions, but the recent spell of unsettled weather (16mm in the last 7 days, 59mm in 28 days) has kept the crag environment saturated, with seepage from the grassy escarpment top likely persisting.
Contributing Factors
7
Nearly 4mm of precipitation fell between midnight and mid-morning, leaving the rock surface wet through the prime climbing hours.
Humidity has been 80–99% for most of the day, inhibiting evaporation and likely maintaining a moisture film on the dense black rock.
The north aspect receives essentially no direct solar radiation, removing the most effective drying mechanism.
The exposed ridgeline position allows wind to strip surface moisture, though today's moderate winds (10–20 km/h) are only partially effective against the high humidity.
Whin Sill dolerite absorbs virtually no water, so only surface moisture needs to evaporate — no deep drying required.
Persistent overcast conditions eliminate any radiative drying from diffuse sunlight.
16mm in the past week and saturated ground above the crag mean seepage and drips from vegetation are likely even where the rock face itself might otherwise be dry.
Recommendations
3
- Wait for the drier spell forecast from August 22 onwards, when dropping humidity and zero precipitation should allow the crag to dry properly.
- If visiting tomorrow or Thursday, arrive mid-afternoon to maximise any drying from the morning breeze, and be prepared to walk away if the rock feels greasy.
- Avoid slab and friction-dependent routes entirely until a full dry day has passed — prioritise steep, well-featured lines with positive holds if conditions allow.
Do Not Climb
65%
63 days ago
Recent persistent rain (7.2mm yesterday, 2.9mm today with showers continuing into the afternoon) and very high humidity leave the north-facing dolerite surfaces likely damp and slippery right now. Although dolerite dries quickly, the combination of ongoing precipitation, 100% cloud cover, and more rain forecast tomorrow and the day after makes today and the immediate days ahead poor for climbing.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is north-facing at 260m on the Whin Sill ridge, meaning it receives essentially no direct sun — drying relies almost entirely on wind, which is strong but insufficient when humidity stays above 85%.
- The dense black dolerite becomes extremely slippery when damp, and even a thin film of moisture from high humidity or light drizzle can make friction-dependent moves treacherous.
- Peregrine falcons nest here in spring; by mid-August nesting restrictions should have lifted, but always check the BMC RAD for current status.
- Crag Lough sits on Hadrian's Wall — a UNESCO World Heritage Site — so avoid any disturbance to the wall, surrounding archaeology, or vegetation on approach.
Warnings
2
- Dolerite is extremely slippery when damp — do not rely on friction-dependent moves until you have confirmed the rock is genuinely dry by touch.
- Heavy rain forecast on August 20 (16.7mm) with NE winds directly onto the north face; conditions will be actively dangerous that day.
Reasoning
Rain fell overnight and into early morning today (nearly 2mm by 04:00), and further showers are forecast from 16:00–18:00; combined with humidity consistently above 80%, the rock surface is almost certainly damp.
Strong westerly winds (~25–33 km/h) would normally dry dolerite within hours, but persistent 85–100% humidity and zero sun on the north-facing aspect severely limit evaporation, keeping surfaces slick.
Whin Sill dolerite does not weaken when wet, but loose blocks at the crag base remain a hazard — heightened slightly by recent wet weather lubricating block interfaces.
Mid-August is peak summer but the recent weather pattern has been unsettled with frequent frontal rain; temperatures are below average for the time of year, further slowing drying.
Contributing Factors
6
2.9mm total today including overnight showers and further rain forecast at 16:00–18:00 means the rock will not get a sustained dry window.
Humidity has been 80–100% throughout today and averaged 81% over the past week, preventing effective evaporation from the rock surface.
Sustained westerly winds of 25–33 km/h across the exposed ridge help strip surface moisture and would allow rapid drying if rain and humidity relented.
The north-facing orientation means essentially no direct solar heating of the rock, making drying entirely dependent on wind and ambient conditions.
Dolerite does not absorb water, so once rain stops and humidity drops, surface moisture can clear within hours rather than days.
5.2mm forecast for August 19 and a further 16.7mm on August 20 will keep surfaces wet through mid-week.
Recommendations
3
- Wait until at least August 21 when the forecast shows a dry day with dropping humidity (74%) and a northerly breeze — conditions should allow the rock to dry within a few hours.
- If visiting on August 21 or 22, test friction on lower holds before committing to harder moves; the black dolerite can appear dry while retaining a thin moisture film.
- Check the BMC RAD for any residual peregrine nesting restrictions before visiting, and respect the Hadrian's Wall UNESCO site on approach.
Do Not Climb
55%
64 days ago
Today saw 8.4mm of rain with heavy showers forecast this evening, and the next several days bring further persistent rainfall; the north-facing dolerite will be wet and extremely slippery. Although dolerite dries quickly, the ongoing precipitation pattern and high humidity leave little opportunity for adequate surface drying.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north-facing aspect receives virtually no direct sun, so surface moisture from rain and condensation lingers far longer than on south-facing dolerite.
- The exposed Whin Sill ridge catches full westerly weather, meaning the frequent W/SW rain systems of recent weeks have kept the crag persistently damp despite the rock's non-porous nature.
- Peregrine falcons nest here in spring — by mid-August restrictions should be lifted, but always check current BMC RAD notices before visiting.
- The crag sits on Hadrian's Wall, a UNESCO World Heritage Site — take care not to disturb archaeological features and stick to established paths and descent routes.
Warnings
3
- Dolerite is extremely slippery when wet — friction loss is sudden and severe, making falls highly likely on technical moves.
- Heavy rain tonight (up to 8mm from 18:00–23:00) will saturate the crag base and approach; beware of loose, waterlogged blocks.
- 10.8mm of rain is forecast for August 20th — conditions will deteriorate further mid-week before improving.
Reasoning
8.4mm fell today with further heavy showers from 18:00 onwards, and yesterday brought 1.9mm — the rock surface is currently wet and will remain so through the night.
Although exposed westerly winds can strip surface moisture from dolerite within hours, the forecast shows rain continuing this evening into tomorrow (3.2mm), so there is no meaningful drying window.
Dolerite does not suffer structural weakening when wet, but loose blocks at the crag base remain a hazard, particularly after the recent wet spell which may have destabilised freeze-thaw-affected material.
Mid-August is normally a reasonable period for climbing here, but the current unsettled Atlantic weather pattern with persistent fronts is keeping conditions poor for this time of year.
Contributing Factors
6
8.4mm total today with over 8mm of heavy showers forecast from 18:00–23:00, ensuring the rock is thoroughly wet.
Rain is forecast on each of the next three days (3.2mm, 3.0mm, 10.8mm), preventing any sustained drying period.
Humidity has averaged 79% over the past week and is forecast at 86–90% for the next three days, slowing evaporation from the rock surface.
Whin Sill dolerite does not absorb water, so it dries rapidly once rain stops and wind picks up — no structural damage concern.
The north-facing orientation means the crag receives no direct sunshine, significantly reducing solar-assisted drying.
The exposed position on the Whin Sill escarpment means wind (forecast 18–28 km/h) can strip surface moisture relatively quickly during dry spells.
Recommendations
3
- Wait until at least August 22nd when a dry day with lower humidity (72%) and clearing skies is forecast, allowing the dolerite to dry properly.
- If you do visit during the wet spell, bring alternative plans — the area offers excellent walking along Hadrian's Wall that doesn't require dry rock.
- Check the rock surface carefully by touch before committing to any route; dolerite can appear dry but retain a thin moisture film that dramatically reduces friction.
Do Not Climb
55%
65 days ago
Today has seen 1.4mm of rain with very high humidity (91%), and the rock is likely still damp on the surface. While dolerite dries quickly in good conditions, the north-facing aspect, high humidity, and moderate wind today mean residual surface moisture is probable, making the dense black rock dangerously slippery.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Crag Lough is north-facing at 260m on the Whin Sill ridge, receiving virtually no direct sun, so surface moisture lingers longer than the rock type alone would suggest.
- The dense black dolerite becomes extremely slippery when even slightly damp — friction loss is far more pronounced than on lighter-coloured rough rock types.
- Peregrine falcons nest here in spring; although the nesting season is largely over by mid-August, check the BMC RAD for any lingering voluntary restrictions.
- Active seepage from the grassy Hadrian's Wall ridge above can persist for days after rain, creating wet bands even when the main face appears dry.
Warnings
2
- The dense black dolerite is extremely slippery when damp — a thin moisture film that is hard to see can cause unexpected falls.
- Loose blocks at the crag base are an active hazard, exacerbated by the recent prolonged wet weather.
Reasoning
Today's 1.4mm of rain combined with 91% humidity means the rock surface is very likely still carrying a moisture film, particularly on this north-facing aspect with no direct sun to drive evaporation.
Moderate westerly wind (17 km/h) on this exposed ridge will help surface drying, but the combination of high humidity and north-facing aspect means drying will be slow — several hours of dry, breezy conditions are needed after today's rain.
Dolerite is non-porous and structurally unaffected by moisture, but loose blocks at the crag base remain a year-round hazard, particularly after the recent wet spell.
Mid-August is within the best window for this venue, but the recent run of unsettled weather with frequent showers and high humidity has kept the crag persistently damp.
Contributing Factors
6
1.4mm of precipitation today with 91% humidity strongly suggests the rock surface is still damp.
The north-facing orientation receives no direct sunlight, removing the most effective drying mechanism for surface moisture.
The high exposed position on the Whin Sill ridge means consistent wind, which helps strip surface moisture even without sun.
Whinstone absorbs virtually no water, so once rain stops and humidity drops, surface moisture can clear within hours.
The last two weeks have seen frequent showers totalling nearly 44mm, keeping seepage lines and vegetation-fed drainage active.
6.3mm forecast for tomorrow with 93% humidity will reset any drying progress, extending unfavourable conditions.
Recommendations
3
- Wait for a sustained dry spell — the forecast suggests 21 August (Friday) as the first realistic opportunity with 0mm rain and dropping humidity.
- If visiting before conditions fully clear, carry a towel and test friction on low-consequence holds before committing to any route.
- Check the BMC RAD for any residual peregrine nesting restrictions and be aware of loose blocks at the crag base after this prolonged wet period.
Climbing Outlook