Forecast check ·
Cadair Idris cloud inversion: 9 July 2026
The quick answer
Yes, the forecast covered Cadair Idris ahead of the morning in the photos. It held over the ridge in 11 of 12 updates, with one wobble along the way.
Barry Mcgauty’s photos from Tyrrau Mawr show a sharp cloud deck below the ridge and blue sky above. This was part of a much bigger morning across Eryri, with sightings further north too.
Very likelyMap for 05:00
- Forecast area
- Southern Eryri and mid Wales
- Tyrrau Mawr on Cadair Idris
- First forecast
- 8 Jul, 07:05 BST
- First useful saved forecast
- Time of event
- 9 Jul, around dawn
- Forecast window: 04:00 to 07:00 BST
- Amount of notice
- About 21 hours
- Before the 04:00 forecast window
What we forecast
The first useful forecast was Very likely with medium confidence. It initially favoured 02:00 to 05:00, then shifted to 04:00 to 07:00 as the day got closer.
What matters to me here is that the area kept coming back over the ridge. One update weakened, but the other eleven kept the opportunity there. That is more useful than picking one good-looking map afterwards.
Above Barmouth and the Mawddach estuary
Tyrrau Mawr sits at the western end of the Cadair Idris massif. Barry’s account describes six and a half hours on the hill, with the inversion still part of the views over the estuary.
There were also photographs from Llyn Dywarchen and Yr Wyddfa that morning. A 06:40 satellite image supported the wider band of low cloud along western Britain.