Glyder Fawr to the Bannau, Wales
Glyder Fawr was on the edge of a Likely area the night before, and Very likely by morning. The webcam was stuck in cloud, but Morgan and Neil were up above it.
Read the forecast checkPeak District & South Pennines
Mam Tor cloud inversion forecast. Next 24 hours.
Next 24 hours
Unlikely
Nothing forming around Mam Tor right now. We’ll email you when that changes.
Captured 21 Oct, 23:10 BST · model rating, not a literal probability
Local outlook
Mam Tor over the next 24 hours
Very likely
Likely
Possible
Purple dot: Mam Tor
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Checked against what happened
Our forecasts, checked
We save each forecast before dawn, then compare it with dated photos of what happened. The nearest check to Mam Tor so far is Glyder Fawr to the Bannau, about 150 km west.
Yr Wyddfa, Wales
By the night before, Yr Wyddfa was Very likely. The summit webcam and a first-hand report both show it above a cloud sea across Eryri.
Read the forecast check
Torridon to Tap o’ Noth, Scotland
The Very likely area over the Highlands held right up to the final update. Walkers at Tap o’ Noth, Torridon and Loch Quoich found cloud below them at dawn.
Read the forecast checkWe’ll publish misses and uncertain calls too, as the record grows.
Browse all forecast checksWhat your free alert looks like
We tell you where and when to look.
When a cloud inversion looks likely near Mam Tor, WeatherDuck emails you up to 24 hours ahead, so you’ve time to check the route and set an alarm.
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- Up to 24 hours of warning
- Likely and Very likely signals
WEATHERDUCK ALERT
Likely cloud inversion
Mam Tor area
Best window05:00–08:00
Conditions are lining up for a cloud inversion. Check the latest forecast before you set off.
Example email · values are illustrativeLocal inversion guide
When can you see a cloud inversion at Mam Tor?
The best chance comes when colder, moist air settles on low ground beneath warmer, drier air, winds stay light and the cloud top remains below your viewpoint.
Mam Tor rises between the Edale and Hope valleys. A useful cloud sea needs low cloud pooled below the ridge while the air above the summit stays drier and clearer.
Fog in Castleton or Edale is encouraging, but it is not enough on its own. A deeper cloud layer can cover the ridge, while shallow valley fog can leave Mam Tor clear above it.
Before you travel: the map shows the wider pattern across Peak District & South Pennines, not a promise for one summit. Check the latest wind, visibility and mountain forecast for your exact route.
See the forecast data and limitationsFind the warm lid
Look for warmer air sitting above colder valley air. That temperature lid is the structure that can trap fog below Mam Tor.
Check Edale and Hope
Moist air needs to collect in the surrounding valleys. The local map shows whether nearby forecast points agree, not just one isolated fog patch.
Keep cloud below 517 m
The most photogenic setup keeps the cloud top below the ridge with noticeably drier air above. If the layer is deeper, Mam Tor may sit inside cloud.
Use the calmest window
Light low-level wind helps the pool hold together. The best chance is usually around dawn, before daytime heating starts to break the layer up.
Plan beyond tomorrow
See the next two days
The public map stays focused on the next 24 hours. Premium extends the detailed inversion map, atmospheric profile and forecast window to two days.
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Browse other Peak District locationsQuick answers
Cloud inversion questions for Mam Tor
Does fog in Castleton or Edale guarantee an inversion on Mam Tor?
No. Valley fog is one useful clue, but Mam Tor also needs the cloud top to stay below the ridge and the air above it to remain clear enough for a view.
Is this a probability for the exact Mam Tor summit?
No. The likelihood band is a regional model signal for the Peak District and South Pennines, supported by nearby captured forecast points. Local cloud can still differ.
Does a Likely signal mean the route is safe?
No. The inversion outlook describes cloud structure, not path, wind, ice, visibility or access safety. Check the full mountain forecast and local guidance before setting out.
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