Look for a firm lid
Warmer, drier air above colder and moister valley air can trap low cloud. The setup is more useful when that structure appears across several nearby model points.
Eryri / Snowdonia & North Wales
Eryri / Snowdonia cloud inversion forecast. Next 24 hours.
See the next 24 hours across Eryri, with the map centred near Capel Curig and a regional signal covering the surrounding valleys and higher mountains.
Local outlook
Eryri / Snowdonia over the next 24 hours
Very likely
Likely
Possible
Map centre: Capel Curig
Latest regional signal
Unlikely
Best window
No clear viewing window yet
Captured 20 Sep, 13:10 BST · model rating, not a literal probability
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The public map stays focused on the next 24 hours. Premium extends the detailed inversion map, atmospheric profile and forecast window to two days.
Local inversion guide
When can you see a cloud inversion in Eryri?
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.
Eryri is cut by deep glacial valleys and high ridges. Cloud can collect around Capel Curig, Nant Gwynant or Ogwen while neighbouring valleys and summits sit in a different layer.
Treat this as a regional planning signal, not one forecast for every summit. Compare the estimated cloud top with your intended viewpoint, then check that mountain's wind, cloud and visibility forecast.
Before you travel: the map shows the wider pattern across Eryri / Snowdonia & North Wales, not a promise for one summit. Check the latest wind, visibility and mountain forecast for your exact route.
See the forecast data and limitationsCompare more than one basin
Capel Curig, Nant Gwynant and Ogwen do not always fill together. Agreement across separated valleys gives a wider cloud sea a better chance.
Match cloud top to the mountain
Eryri has no single useful viewing height. The low cloud needs to remain below the ridge or summit you intend to use, with clearer air above it.
Follow the overnight trend
A signal that strengthens through calm overnight hours and holds around dawn is more convincing than one brief forecast spike.
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Cloud inversion questions for Eryri / Snowdonia
How is this different from the Yr Wyddfa inversion page?
This page covers the wider Eryri and North Wales regional signal. The Yr Wyddfa page uses a closer map and guidance specific to the mountain and its surrounding approaches.
Will every Eryri valley have the same cloud inversion?
No. Wind direction, moisture and terrain can fill one valley while another stays clear or sits under deeper cloud. Use the timeline and compare several areas.
Does a Likely signal mean Eryri routes are safe?
No. The outlook describes cloud structure only. Check wind, rain, ice, visibility, route conditions and official mountain-safety advice for the exact route you plan to use.
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