Forecast check · 22 September 2026

Yr Wyddfa cloud inversion: 22 September 2026

The quick answer

Yes, the forecast picked out the right area and morning. But the cloud sea lasted well beyond the window we gave it.

The webcam showed Yr Wyddfa clear above the cloud at 08:06. By 10:54 it was still there. That is the bit I want to get better at: spotting when a good morning is going to keep going.

First useful forecastSaved Sun 20 Sep, 21:04 BST

LikelyMap for 07:00

Archived WeatherDuck forecast saved on 20 September 2026 at 21:04 BST, about 31 hours ahead of the dawn window, showing a Likely area over Eryri for 07:00 on 22 September. The purple dot marks the review point on Yr Wyddfa.

Forecast area: Eryri and mid Wales; Yr Wyddfa, above Llanberis
First forecast: 20 Sep, 21:04 BST; First useful saved forecast
Time of event: 22 Sep, morning; Webcam frames at 08:06 and 10:54 BST
Amount of notice: About 31 hours; Before the 04:00 forecast window

What we forecast

The first useful forecast covered Yr Wyddfa on Sunday evening, with Tuesday dawn at Likely. It strengthened to Very likely the night before, then settled back to Likely in the three updates before dawn.

The area held over the summit in 13 of 17 updates. Four weakened on Monday afternoon and evening, so it was not a completely steady run. An earlier signal around 51 hours ahead fell away and is not counted here.

Archived WeatherDuck map showing a Very likely cloud inversion area over Eryri and mid Wales for 04:00 on 22 September 2026, saved on 21 September. — Forecast saved 21 September at 21:05 BST, shown for 04:00 BST on 22 September: Very likely over the summit the night before. The fixed purple dot marks the review point on Yr Wyddfa.

Archived WeatherDuck map showing a Likely cloud inversion area over most of Wales for 06:00 on 22 September 2026, saved at 05:03 that morning. — Forecast saved 22 September at 05:03 BST, shown for 06:00 BST, two hours before the first webcam frame. The fixed purple dot marks the review point on Yr Wyddfa.

Still above the cloud later that morning

The webcam frames and Snowdon Mountain Railway’s summit photo show why one forecast end time does not tell the whole story. The view from Hafod Eryri was pretty special.

Webcam images: DataCymru Ltd, snowdon.webcam, CC BY 4.0. Thanks to Snowdon Mountain Railway for permission to use the summit photo. Their reel from the morning.

Webcam frame at 08:06 BST on 22 September 2026: Yr Wyddfa clear against blue sky in golden light, with cloud pouring over a lower ridge below the summit and a cloud sea to the right. — Yr Wyddfa from the north at 08:06 BST on 22 September 2026, an hour after sunrise, with cloud spilling over a lower ridge below the clear summit. Snowdon Webcam image by DataCymru Ltd, snowdon.webcam, CC BY 4.0, shown with its original watermark and timestamp.

Webcam frame at 10:54 BST on 22 September 2026: the cloud deck billowing over the lower ridge below Yr Wyddfa, with the summit still clear and fair-weather cloud above. — The same view at 10:54 BST, two to three hours after the forecast expected the cloud sea to break up, with the deck still spilling over the ridge and the summit still clear. Snowdon Webcam image by DataCymru Ltd, snowdon.webcam, CC BY 4.0, shown with its original watermark and timestamp.

The summit of Yr Wyddfa on 22 September 2026: the Hafod Eryri building and walkers in bright sun above an unbroken cloud sea filling every valley, with only the summit ridge and one distant top breaking through. — On the summit later that morning: Hafod Eryri and the summit ridge above an unbroken cloud sea. Photo by Snowdon Mountain Railway (original post), used with permission.