Condition Analysis
AI-powered assessment using site data and 14-day weather history
Castle Rock has been subjected to an extremely wet period — 51.7mm on April 11 followed by 11.4mm on April 12 — with only a trace-dry day today; the crag is almost certainly still damp, especially on seepage-prone north crag sections. With more rain forecast from tomorrow, conditions are not expected to improve this week.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines will be actively running after 63mm of rain in the last 48–72 hours, and these can take days to fully dry even on non-porous rock.
- The W/NW aspect means the crag receives no morning sun and only limited afternoon sun in April — drying today relies almost entirely on the moderate southerly wind at ~19 km/h, which is insufficient to clear heavy saturation quickly.
- At 300m altitude with overnight temperatures near freezing (min 1.7°C today), any residual moisture in cracks and on ledges may have partially frozen overnight and will thaw slowly through the day, keeping surfaces damp.
- Peregrine nesting restrictions may be in effect at Castle Rock in April — check BMC Regional Access Database before visiting.
Warnings
3
- Seepage lines on the north crag will be actively weeping and may persist for several days after this volume of rainfall.
- Friction on wet BVS rhyolite is extremely poor — do not be deceived by rock that appears superficially dry on prominent features while recesses and slabs remain damp.
- The prolonged wet spell (170mm in 28 days) means the entire hillside is saturated; water will continue to seep through cracks and drainage lines even without further rain.
Reasoning
With 51.7mm on April 11 and 11.4mm on April 12, the rock surface and all seepage lines are heavily saturated; today's trace precipitation (0.1mm) and high humidity (79%) provide minimal drying opportunity.
Only ~18 hours have passed since the last meaningful rain, with moderate southerly winds (~19 km/h) offering partial exposure on this W/NW face — far too little time to clear the volume of water from this prolonged wet spell.
BVS rhyolite does not suffer structural damage when wet, so hold breakage is not a concern; the risk is entirely friction-related.
Early April in the Lake District at 300m means short daylight hours for drying, cool temperatures (avg 5.3°C over the last week), and the crag is still in its winter-to-spring transition with persistently high background moisture levels.
Contributing Factors
8
63.1mm fell on April 11–12, following an already saturated period with 169.9mm in the last 28 days — the crag is heavily waterlogged.
Only about 18 hours since meaningful rain ceased, with zero consecutive fully dry days recorded.
Humidity today at 79% with last-week average at 78% severely limits evaporative drying of surface moisture.
Southerly winds at ~19 km/h provide some airflow across the partially exposed crag, aiding surface evaporation to a limited degree.
BVS rhyolite does not absorb water, so surface moisture can clear relatively quickly once rain stops and conditions improve — but conditions have not yet improved sufficiently.
Max 6.4°C today at 300m with overnight lows near freezing slows evaporation and extends drying time significantly.
4.7mm forecast for April 14 followed by 10mm on April 15 means any partial drying today will be immediately reversed.
The crag receives no direct morning sun and only limited afternoon exposure, reducing solar-driven drying significantly in early April.
Recommendations
3
- Do not climb today — the crag is almost certainly damp across most lines following the heavy rain of April 11–12, and friction on wet rhyolite is dangerously poor.
- Monitor weather closely for a window of 2+ dry days with good wind; the earliest realistic opportunity may be April 17–18 if the forecast holds.
- Check BMC RAD for peregrine nesting restrictions at Castle Rock before planning any spring visit.
Previous Analyses
Do Not Climb
92%
2 days ago
Castle Rock of Triermain is currently wet and unsuitable for climbing. A massive 51.7mm fell yesterday followed by nearly 10mm today, with no dry days to allow any drying — the rock will be saturated with surface water and seepage lines will be actively running.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines will be heavily active after 61mm of rain in the last two days on top of an already saturated catchment.
- The W/NW aspect receives limited direct sun in early April, and today's overcast, humid conditions (89%) will provide virtually no solar drying.
- The crag sits at 300m in a mountain environment where temperatures have been hovering around 0–5°C, significantly slowing evaporation even with moderate wind.
- The cumulative 181mm over 28 days means the ground and any cracks or ledges above the crag are thoroughly saturated, feeding persistent drainage onto the rock face.
Warnings
2
- Active seepage lines and surface water make steep trad routes (Overhanging Bastion, North Crag Eliminate) extremely dangerous due to near-zero friction on wet rhyolite.
- The mountain atmosphere at Castle Rock means conditions can deteriorate rapidly; do not be caught high on the crag if further rain arrives.
Reasoning
The rock surface is certainly wet today, with 51.7mm falling yesterday and 9.7mm today on top of a prolonged wet spell totalling 181mm over 28 days — surface water, seepage, and drainage will all be active.
Zero consecutive dry days and high humidity (89%) mean no meaningful drying has occurred; even with moderate SW winds at 33.5 km/h, the ongoing precipitation today prevents any surface drying.
BVS rhyolite is non-porous and will not suffer structural damage from the saturation, but friction is drastically reduced on wet volcanic rock, making steep routes extremely dangerous.
Early April in the Lake District at 300m brings short days, low sun angles, cool temperatures averaging just 5.3°C, and the W/NW aspect misses much of whatever weak sun is available — all of which compound slow drying.
Contributing Factors
7
51.7mm yesterday and 9.7mm today constitute an extreme wetting event, ensuring the entire crag face is running with water.
There have been no consecutive dry days, so no drying window has been available since the deluge began.
Humidity at 89% today severely limits evaporative drying even where wind reaches the rock.
181mm over 28 days means the ground above the crag is fully saturated, feeding seepage lines and drainage channels onto the face.
Temperatures averaging 5.3°C over the past week provide minimal thermal energy for evaporation.
SW winds at 33.5 km/h would aid drying if precipitation stopped, but cannot overcome active rainfall and saturated conditions.
BVS rhyolite does not absorb water so will dry relatively quickly once rain stops and conditions improve, but that window has not yet arrived.
Recommendations
3
- Do not attempt to climb today — the crag will be thoroughly wet with active seepage and dramatically reduced friction on the steep routes.
- Monitor conditions from April 13th onwards; a dry day with lower humidity is forecast, but a full assessment on arrival will be essential before committing.
- Check BMC RAD for peregrine nesting restrictions at Castle Rock before planning any spring visit.
Do Not Climb
95%
3 days ago
Castle Rock of Triermain is receiving nearly 40mm of rain today with no preceding dry period — the crag will be thoroughly saturated and actively wet. With ongoing rain forecast tomorrow and persistent moisture through the week, conditions are clearly unsuitable for climbing today.
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 today's southerly-driven rain and will receive no direct sun until the afternoon, prolonging surface wetness.
- Known seepage lines on the North Crag will be running heavily given 47mm in the last 7 days and nearly 40mm today alone — these can persist for days after heavy rain events.
- The crag sits at 300m in a mountain environment where temperatures are hovering near freezing overnight, meaning any residual moisture could form verglas on the rock surface in early morning.
- Peregrine nesting restrictions may be active at this time of year (April) — climbers should check the BMC Regional Access Database before planning a visit.
Warnings
3
- The crag is receiving extreme rainfall (nearly 40mm today) — rock surfaces will be dangerously slippery and seepage lines will be active.
- Overnight temperatures near or below freezing combined with saturated rock create a verglas risk on early-morning approaches and rock surfaces.
- Peregrine nesting restrictions may be in effect — check BMC RAD before visiting.
Reasoning
The rock is actively being rained on with 39.8mm today, following 47.4mm in the past week and 162.2mm over 28 days — the surface will be streaming wet with seepage lines fully charged.
Zero consecutive dry days and strong SW winds driving moisture directly onto the W/NW face mean there has been no meaningful drying; the partial wind exposure is irrelevant when the crag is being actively rained upon.
BVS rhyolite does not suffer structural damage when wet, but the extreme surface moisture will reduce friction to dangerously low levels on this steep crag.
Early April in the Lakes at 300m brings low temperatures (near or below freezing overnight), short effective drying windows, and high background humidity — a prolonged wet spell like this takes considerable time to clear.
Contributing Factors
6
39.8mm of precipitation today alone makes the crag actively wet and streaming — climbing is impossible in these conditions.
47.4mm in the last 7 days and 162.2mm over 28 days mean the ground and seepage lines are thoroughly charged with water.
There have been zero consecutive dry days leading into today, so no drying window has occurred since the last rain.
The southerly wind at 40 km/h is driving rain directly onto the W/NW face rather than aiding drying.
Max of 3.1°C today with overnight frost risk limits evaporation rates and could produce verglas on damp rock.
BVS rhyolite will not suffer structural damage, but the friction loss on wet volcanic rock on steep routes like Overhanging Bastion is a serious safety hazard.
Recommendations
3
- Do not visit today — the crag is actively wet and conditions are dangerous on steep routes.
- Monitor conditions from April 16 onward; a meaningful dry window of at least 24 hours with wind and some sun will be needed before the crag is climbable.
- Check the BMC RAD for peregrine nesting restrictions before planning any visit, as April is peak nesting season at Lake District crags.
Do Not Climb
85%
4 days ago
Castle Rock of Triermain is currently wet following rain yesterday (4.2mm) and today (1.1mm), with persistent high humidity and no consecutive dry days. The recent period has been exceptionally wet with 132.8mm over 28 days, and heavy rain is forecast tomorrow (30.2mm), making conditions clearly unsuitable.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines will be actively running after the prolonged wet spell — over 130mm in 28 days ensures deep seepage is well-charged and will persist for days after rain stops.
- The W/NW aspect means the crag receives no morning sun and only limited afternoon sun at this time of year, significantly slowing surface drying on cool spring days.
- At 300m altitude with overnight temperatures near or below freezing, any residual moisture may form verglas or thin ice on the rock surface in early morning, creating an invisible hazard on the steep routes.
- Peregrine nesting season is underway (April); climbers should check BMC RAD for any active restrictions before planning a visit to Castle Rock.
Warnings
3
- Overnight frost risk with wet rock could produce invisible verglas on the steep routes — extremely dangerous on Overhanging Bastion and similar exposed lines.
- Seepage lines on the north crag will be running heavily after the prolonged wet spell; these can make normally dry holds unexpectedly slick.
- 30mm+ of rain forecast tomorrow — do not plan a visit for the next two days under any circumstances.
Reasoning
The rock is currently wet from today's 1.1mm of rain on top of yesterday's 4.2mm, and the 28-day total of 132.8mm means seepage lines on the north crag will be well-charged and actively weeping.
Zero consecutive dry days and SW winds at ~30 km/h provide some surface drying, but the W/NW aspect limits direct sun exposure and cool temperatures (4.8°C max today) slow evaporation significantly.
Borrowdale Volcanic Series rhyolite is non-porous and does not suffer structural damage when wet, so rock integrity is not a concern.
Early spring conditions at 300m bring overnight frost risk (min 0.2°C today, forecast lows to -3.6°C), high ambient humidity averaging 77% over the past week, and short effective drying windows — all of which prolong surface moisture retention.
Contributing Factors
8
1.1mm of precipitation today with no dry hours to allow surface drying means the rock is currently wet.
132.8mm over 28 days with rain on most days has saturated the ground and recharged all seepage lines on the crag.
There has been no sustained dry period to allow even surface drying, let alone clearing of seepage lines.
30.2mm forecast for April 11th will thoroughly re-wet the crag and extend the drying timeline significantly.
Max temperature today only 4.8°C with overnight lows near freezing slows evaporation and creates potential verglas hazard.
SW winds at ~30 km/h provide some surface drying effect on the partially exposed crag.
BVS rhyolite does not absorb water so surface moisture can evaporate quickly once rain stops and conditions improve, and structural damage is not a concern.
Average humidity of 77% over the past week significantly retards evaporative drying from the rock surface.
Recommendations
3
- Do not climb today — the crag is wet and conditions will worsen significantly tomorrow with 30mm+ of rain forecast.
- The earliest realistic window is April 14th after a forecast dry day on the 13th–14th, but check conditions on arrival as seepage lines may persist.
- Check BMC RAD for peregrine nesting restrictions at Castle Rock before planning any visit during April–June.
Do Not Climb
45%
5 days ago
Castle Rock of Triermain has received 1.2mm of rain today following a very wet recent period (172mm in 28 days), and with humidity currently at 87% and the NW-facing aspect receiving minimal direct sun, surface moisture and seepage are likely present. The crag had a brief dry spell from April 6–8 but today's rain and high humidity will have re-wetted surfaces, reducing friction on the volcanic rock.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines will likely be active given 37.9mm fell on March 24 and repeated rain since, meaning persistent weeping even where surface rock appears dry.
- The W/NW aspect means the crag misses morning sun entirely and only catches weak afternoon sun at this time of year, significantly slowing surface drying after today's rain.
- At 300m altitude in early April, overnight temperatures are dropping near or below freezing (min 0.8°C today), so any residual moisture could form thin ice or frost on shaded holds in early morning.
- Peregrine nesting restrictions may be in effect — climbers should check the BMC Regional Access Database (RAD) before visiting, as Castle Rock has historically had seasonal bird restrictions.
Warnings
3
- Active seepage lines on the north crag are likely given the extremely wet recent period — avoid North Crag Eliminate and adjacent routes until a sustained dry spell.
- Near-freezing overnight temperatures may produce frost or verglas on shaded holds in early morning; do not start climbing before the rock has warmed above freezing.
- Today's rain and high humidity mean friction on the volcanic rock will be significantly reduced — falling risk is elevated on steep or technical routes like Overhanging Bastion.
Reasoning
Today's 1.2mm of precipitation on top of already saturated ground and high ambient humidity (87%) means surface moisture is very likely present across the crag, particularly on the north-facing sections.
Although April 6–8 were dry with good temperatures (up to 14.5°C) and moderate SW winds, only two full dry days preceded today's return of rain, which is insufficient to clear seepage lines fed by the extremely wet March (172mm in 28 days).
BVS rhyolite is non-porous and not at risk of structural damage when wet; the concern is purely friction loss and climber safety on damp surfaces.
Early April at 300m in the Lake District means short daylight drying windows, weak solar angle on a NW aspect, and near-freezing overnight temperatures that can produce frost or condensation on the rock.
Contributing Factors
8
1.2mm of precipitation today has re-wetted rock surfaces that were beginning to dry after the brief April 6–8 dry window.
172mm over 28 days has thoroughly saturated the ground and hillside, feeding persistent seepage lines on the north crag.
Humidity at 87% today with overnight readings reaching 96% will inhibit evaporation and may produce condensation on the cold rock surface.
Three dry days with temperatures up to 14.5°C and moderate winds provided some surface drying, though insufficient to clear deeper seepage.
The predominantly NW-facing rock receives minimal direct sunlight in early April, greatly limiting solar-assisted drying.
SW winds at 32 km/h today provide some wind-assisted drying, partially offsetting the poor solar aspect.
Minimum of 0.8°C today at 300m means frost or thin ice may form on shaded holds during early morning hours.
BVS rhyolite does not absorb water, so surface moisture is the only concern and it can dry relatively quickly once rain stops and conditions improve.
Recommendations
3
- Wait for at least two consecutive dry days with humidity below 75% before attempting routes, particularly on the north crag where seepage persists longest.
- If you do visit, focus on the most exposed, west-facing sections that catch afternoon sun and wind, and avoid any routes with visible seepage or dampness.
- Check the BMC RAD for current peregrine nesting restrictions at Castle Rock before planning a trip.
Marginal — Assess Conditions
68%
6 days ago
Three consecutive dry days with warm temperatures (up to 14.5°C) and moderate SW winds have likely dried the main rock surfaces, but the preceding very wet period (174mm in 28 days) and known seepage lines on the north crag mean some damp patches may persist. A visual check on arrival is strongly advised before committing to routes.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's seepage lines are likely still active given 37.9mm fell on March 24th and repeated smaller pulses since, so routes on the north crag should be treated with particular suspicion.
- The W/NW aspect means the crag only receives direct afternoon sun, and the last two days' southerly winds would have blown across rather than directly onto the main face, slightly reducing drying efficiency.
- At 300m altitude the overnight temperatures have been near or just below freezing in recent weeks, and any residual seepage could form thin ice on shaded holds during early morning — check carefully if arriving before midday.
- April is within the peregrine nesting restriction window; climbers should check the BMC Regional Access Database for any current closures at Castle Rock before visiting.
Warnings
2
- Seepage lines on the north crag may still be active despite surface drying — wet volcanic rock is extremely slippery and falls from friction loss on steep terrain here would be serious.
- Rain returns tomorrow (April 9th) and persists through the coming week; today is likely the only viable window for several days.
Reasoning
The rock surface should be largely dry after three rain-free days including yesterday's exceptional drying conditions (14.5°C, 48% humidity, 35 km/h wind), but deep seepage lines fed by the very wet preceding month may still be weeping.
Yesterday's warm, low-humidity, windy conditions provided excellent surface drying for non-porous volcanic rock, though the W/NW aspect limits morning sun exposure and the southerly wind direction is not ideal for this face.
Borrowdale Volcanic rhyolite is non-porous and not at risk of structural damage from moisture; the concern is purely friction loss on any remaining damp surfaces.
Early April in the Lake District is transitional — overnight frost is still possible at 300m, daylight hours are reasonable but limited, and the recent wet spell is typical of spring in the western Lakes.
Contributing Factors
7
No rain since April 5th (1.9mm), with April 6th, 7th, and today all dry, giving non-porous rock adequate surface drying time.
April 7th saw 14.5°C, humidity dropping to 34%, and sustained 35 km/h winds — outstanding drying conditions for volcanic rock.
174mm over 28 days with repeated rain pulses means groundwater levels are high and seepage lines are likely still active.
The crag only catches afternoon sun, so any overnight condensation or residual dampness persists longer into the day.
Humidity is forecast at 77% today, up from yesterday's low of 34%, indicating moister air and reduced evaporative drying.
Sustained 30+ km/h SW winds provide reasonable airflow across the face, aiding surface drying.
4.1mm forecast for April 9th with 95% humidity signals the end of this dry window and makes today the best opportunity.
Recommendations
3
- Visit this afternoon to maximise benefit from the W-facing aspect's direct sun and the cumulative drying effect of three dry days.
- Avoid the north crag and known seepage lines — focus on the better-drained, more exposed sections of the main buttress.
- Check the BMC RAD for peregrine nesting restrictions before setting out, as April falls within the sensitive nesting period.
Marginal — Assess Conditions
55%
8 days ago
After a very wet period, today is the first fully dry day with dropping humidity and moderate southerly wind, which should help surface drying on this non-porous volcanic rock. However, only one dry day following sustained heavy rainfall means seepage lines and sheltered sections of the crag are likely still damp, so on-site assessment is essential before committing to routes.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- Castle Rock's north crag seepage lines are almost certainly still active after 35mm in the last week and nearly 200mm in the past month, so routes on the north crag should be treated with particular caution.
- The W/NW aspect means the crag will not receive direct sun until the afternoon — morning visits today will find the rock slower to dry despite the southerly breeze.
- At 300m altitude with overnight lows near freezing, any residual moisture on the rock surface may have formed a thin ice film early this morning that should melt through the day as temperatures rise toward 8°C.
- Peregrine nesting restrictions may be in effect at Castle Rock in early April — check BMC RAD and local notices before approaching the crag.
Warnings
3
- Check BMC RAD for peregrine nesting restrictions at Castle Rock — seasonal closures may be in effect in early April.
- Seepage lines on the north crag are very likely still active and routes there should be considered wet until visually confirmed dry.
- Overnight sub-zero temperatures at crag altitude may have left icy patches on ledges and in cracks — take extra care on the approach and during climbing.
Reasoning
The rock received 1.9mm yesterday and scattered light precipitation through the morning of April 5th, with only the last ~18 hours being properly dry; combined with 35mm over the past week and very high average humidity (88%), surface moisture and seepage are likely still present in sheltered areas.
Today's dry conditions (0mm, humidity dropping to 73%, moderate 25 km/h southerly wind) will promote surface drying on exposed faces, but the W/NW aspect limits direct solar heating to afternoons, and one dry day is marginal for clearing seepage lines after such a prolonged wet spell.
As Borrowdale Volcanic Series rhyolite, there is no structural risk from moisture — the rock does not weaken when wet — but overnight temperatures near 0°C after recent saturation could mean minor freeze-thaw spalling on loose blocks.
Early April in the Lake District at 300m is still a marginal season with short days, cold overnight temperatures, and frequent Atlantic weather systems; the recent pattern of persistent rain is typical for this time of year.
Contributing Factors
7
35mm in the past 7 days and 191mm in the past 28 days represents a very saturated catchment, likely feeding persistent seepage lines on the crag.
Today is forecast completely dry with 0mm precipitation, giving the rock its first full day to shed surface moisture.
Humidity has fallen from the high 80s–90s to 73% today, which significantly aids evaporative drying of surface moisture on non-porous rock.
A 25 km/h southerly breeze will help strip moisture from exposed faces, though the W/NW aspect means the wind may not reach all sections equally.
The crag will only receive direct sunlight in the afternoon, meaning morning conditions will be noticeably damper and colder.
Overnight lows near 0.7°C at valley level (likely sub-zero at 300m) may have caused any residual surface moisture to freeze, creating icy patches in shaded areas early in the day.
BVS rhyolite does not absorb water, so once surface moisture evaporates the rock will offer its characteristic excellent friction — no extended internal drying period required.
Recommendations
3
- Visit in the afternoon when the W/NW aspect will have received direct sun and maximum drying time; avoid morning sessions.
- Focus on the most exposed and steepest sections of the crag which will dry fastest; avoid the north crag where seepage lines are known to persist.
- Touch-test holds and friction-test the rock on lower, easy ground before committing to any route — if the surface feels glassy or slick, back off and return another day.
Do Not Climb
30%
9 days ago
Castle Rock has received persistent heavy rainfall over the past month (190mm in 28 days) with 0.8mm today, high humidity averaging 90%, and near-freezing temperatures — the rock will almost certainly still have residual surface moisture and active seepage lines despite strong westerly winds. We recommend waiting; tomorrow (April 6th) looks far more promising with a dry, warmer day forecast.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines will be actively running after 35mm in the past week and 190mm over 28 days — these persist for days after heavy rain and are slow to dry on the NW aspect.
- The W/NW aspect means no direct morning sun; any afternoon drying today will be minimal given the 1.8°C max temperature and overcast conditions.
- At 300m altitude with overnight lows around -0.5°C, freeze-thaw is a concern — any residual moisture in cracks may have frozen overnight and could create icy patches on the rock surface.
- Peregrine nesting restrictions may be in effect at this time of year (April) — climbers should check BMC RAD for current access status before visiting.
Warnings
3
- The rock surface is very likely wet or damp today — climbing on wet BVS rhyolite carries serious fall risk due to dramatically reduced friction.
- Overnight freezing temperatures may have created ice in cracks and on ledges; take extra care on approach and at the crag base.
- Seepage lines on the north crag are likely to persist for several days given the volume of recent rainfall.
Reasoning
With 0.8mm of precipitation today, 14.8mm yesterday, and 11.9mm the day before, the rock surface is almost certainly wet, and persistent seepage lines on the north crag will be well-charged after a very wet month.
The strong westerly wind (55.8 km/h) will aid surface evaporation, but the near-freezing temperature (1.8°C max), high humidity (82%), and lack of direct sun on the W/NW aspect until afternoon severely limit drying potential today.
BVS rhyolite is non-porous and does not suffer structural damage when wet, so there is no rock conservation concern — the issue is purely friction and safety.
Early April at 300m altitude in the Lake District is a marginal season with low temperatures, frequent frost, short effective drying windows, and potential peregrine nesting restrictions.
Contributing Factors
7
Today saw 0.8mm with 14.8mm yesterday and 11.9mm the day before — the rock has had essentially no dry period to shed moisture.
190mm over 28 days means the ground is saturated and seepage lines on the crag will be actively running.
Average humidity of 90% over the past week severely limits evaporative drying from rock surfaces.
A maximum of only 1.8°C today with overnight lows of -0.5°C means negligible thermal drying and possible ice in cracks.
Winds of 55.8 km/h from the west will help strip surface moisture from this W/NW-facing crag, but cannot overcome the volume of recent rain.
The crag receives no direct sun until afternoon, and in early April with low sun angles and likely cloud cover, solar drying contribution is minimal.
A dry day forecast for April 6th with 6.9°C, 71% humidity, and lighter winds suggests conditions should improve significantly by tomorrow afternoon.
Recommendations
3
- Wait until tomorrow (April 6th) when a dry, warmer day with lower humidity should allow meaningful drying — afternoon sessions will benefit from the W/NW aspect catching the sun.
- Check BMC Regional Access Database for current peregrine nesting restrictions at Castle Rock before planning a visit.
- If visiting tomorrow, start with lower, more exposed routes and visually inspect seepage lines on the north crag before committing to climbs there.
Do Not Climb
90%
10 days ago
Castle Rock of Triermain is currently wet and unsuitable for climbing. Today has seen 6.8mm of rain with 90% humidity, following a persistently wet period with 36mm in the last week and over 180mm in the last 28 days — seepage lines on the north crag will be running heavily.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
- The north crag's known seepage lines will be very active after 180mm+ of rain in the past month, and these can persist for days even after surface rock dries.
- The W/NW aspect means the crag receives no direct sun until afternoon, significantly slowing morning drying — especially problematic in early spring with low sun angles.
- At 300m altitude with overnight temperatures near or below freezing, any residual moisture may form verglas on shaded holds during early morning approaches.
- Peregrine nesting restrictions may be in effect at this time of year — climbers should check the BMC RAD database before planning a visit.
Warnings
3
- Active rain and saturated rock make climbing extremely dangerous today — steep routes like Overhanging Bastion rely on friction that is absent when wet.
- Overnight temperatures near or below freezing may produce verglas on damp rock surfaces during morning approaches.
- Seepage lines on the north crag are likely to persist for several days even after rain stops given the saturated conditions.
Reasoning
The rock is currently wet from today's 6.8mm rainfall on top of an extremely wet preceding month (181.7mm over 28 days, 36.2mm in the last 7 days alone), with zero consecutive dry days and 90% humidity.
Despite strong SW winds today (59.4 km/h), ongoing rain and near-saturated air prevent any meaningful drying; the W/NW aspect and low spring sun angle further limit evaporative potential.
BVS rhyolite is non-porous and does not suffer structural damage when wet, so hold breakage is not a concern — but friction loss on the steep routes here is a serious safety issue.
Early April in the Lake District at 300m is still a marginal season with low temperatures (average 3.4°C over the last week), short effective drying windows, and possible overnight frost creating icy conditions on damp rock.
Contributing Factors
6
6.8mm of rain today with 90% humidity means the rock is actively wet right now.
Over 180mm in 28 days with no consecutive dry days means the ground and seepage lines are fully saturated.
Average humidity of 91% over the past week severely inhibits evaporative drying even between rain events.
SW winds of 59 km/h today and forecast to remain moderate will assist surface drying once rain stops.
Average temps of 3.4°C and overnight frosts slow drying and risk verglas on damp holds.
The W/NW facing crag receives limited and late direct sunlight in early April, reducing solar drying.
Recommendations
3
- Do not climb today — the rock is actively wet and friction on the steep BVS routes will be dangerously reduced.
- Monitor conditions for the dry window forecast on April 6–7; if these days materialise as predicted, assess conditions on arrival, particularly checking seepage lines on the north crag.
- Check the BMC Regional Access Database for any active peregrine nesting restrictions at Castle Rock before planning a visit.
Do Not Climb
90%
11 days ago
Castle Rock of Triermain is currently wet and unsuitable for climbing. Today has seen 8.6mm of rain with 94% humidity, following an extremely wet period (182mm in 28 days) with zero consecutive dry days — seepage lines on the north crag will be running and friction on the volcanic rock will be severely compromised.
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 flowing after nearly 28mm of rain in the past week and 182mm over 28 days, making routes like North Crag Eliminate particularly affected.
- The W/NW aspect receives no morning sun and limited afternoon sun in early April, meaning surface moisture from today's rain will linger well into tomorrow, especially in shaded gullies and corners.
- Strong SW winds (37 km/h today) hit the crag's exposed west face directly, which aids surface drying but also drives rain onto the climbing surfaces during precipitation events.
- Peregrine nesting restrictions may be in effect at this time of year — climbers should check BMC RAD for any current seasonal closures before planning a visit.
Warnings
3
- Active rain and saturated seepage lines make all routes dangerously slippery today — do not attempt to climb.
- Overnight frost at 300m following wet conditions can produce verglas on damp rock surfaces, particularly on the north crag.
- Peregrine nesting restrictions may be in force — verify with BMC RAD before visiting.
Reasoning
The rock is currently wet from today's 8.6mm of rain, compounded by persistent moisture from a relentlessly wet period with 27.3mm in the last 7 days and 91% average humidity.
With zero consecutive dry days, strong SW winds provide some drying potential but are currently driving rain onto the west-facing crag; meaningful drying cannot begin until precipitation stops and humidity drops below 80%.
Borrowdale Volcanic Series rock is non-porous and not at risk of structural damage from moisture, but freeze-thaw cycles (overnight minima near or below 0°C) could affect loose blocks at altitude.
Early April in the Lake District at 300m is a marginal season with short days, low sun angles, persistent dampness, and potential frost — the crag is not yet in its reliable climbing season.
Contributing Factors
7
8.6mm of rain today with 94% humidity means the rock is currently wet across all faces.
182mm over the past 28 days with zero consecutive dry days has saturated the ground and ensured seepage lines are actively running.
Average humidity of 91% over the last 7 days prevents effective evaporation and keeps surfaces damp even between rain events.
Winds of 37 km/h aid surface evaporation in dry spells but are currently driving rain directly onto the west-facing crag.
The W/NW aspect receives only limited afternoon sun in early April, with north-facing sections in shade all day, significantly slowing drying.
Overnight minima near or below freezing at 300m slow drying and create potential for icy patches on damp rock in the early morning.
BVS rhyolite does not absorb water so once rain stops and surfaces dry, the rock will not be structurally compromised.
Recommendations
3
- Do not climb today — the crag is wet and friction on the volcanic rock will be dangerously poor.
- Monitor the forecast for April 6–7 which shows two consecutive dry days with dropping humidity — this is the earliest realistic window for climbing.
- Check BMC RAD for peregrine nesting restrictions at Castle Rock before planning any visit during March–June.
Climbing Outlook