Tuesday 22 September 2026 was one of those mornings. From Yr Wyddfa in the north to Pen y Fan in the south, the big Welsh summits sat above a sea of cloud from before dawn until well after breakfast, and WeatherDuck had flagged it from the Sunday evening. Here’s how the morning looked, thanks to the people who were up there: Neil Hollis on Pen y Fan and Snowdon Mountain Railway on the summit of Yr Wyddfa.
What did the forecast say?
The first useful signal came at 21:04 on Sunday 20 September, about 31 hours ahead: a Likely area over Eryri and mid Wales for Tuesday’s dawn. It wobbled on the Monday afternoon, then came back stronger, and by Monday evening the summits sat inside a Very likely area for the small hours. The final updates before dawn stretched the area south as far as Bannau Brycheiniog.
For the full story of how the forecast held up, update by update, read the Yr Wyddfa forecast verification report.
Pen y Fan under the stars
Neil Hollis headed up Pen y Fan in the dark because he had a hunch there’d be some kind of cloud inversion. He was right. Mist filled the valleys below, the lights of the towns glowed up through it, and the sky above was about as clear as it gets. In his words, “It was some kind of sight having the place all to myself!”
Left: the Milky Way over the cloud sea from Pen y Fan, with the Andromeda Galaxy top left. Right: along the ridge before dawn. Photographs: Neil Hollis (@neilhollis on Instagram), used with permission.
Yr Wyddfa at sunrise
Up north, the snowdon.webcam camera above Llanberis caught the summit sharp against blue sky an hour after sunrise, with cloud pouring over the lower ridge below it like a slow waterfall.
On the summit itself, Snowdon Mountain Railway‘s photo at the top of this post shows Hafod Eryri and the walkers who’d made it up standing in bright sunshine, with an unbroken white sea in every valley. Top photograph: Snowdon Mountain Railway (original post on Facebook), used with permission.
The railway also shared a reel from that morning, and it’s well worth a watch: see it on Facebook.
Still going mid morning
Our forecast expected the cloud sea to break up around 08:00 to 09:00. It didn’t read the script. At 10:54 the deck was still spilling over the ridge below Yr Wyddfa, with the summit still in the sun, so anyone who set off late still got a show.
Catch the next one
Autumn and winter are cloud inversion season, and mornings like this come round more often than you’d think. Keep an eye on the UK cloud inversion forecast, or check the outlook for Yr Wyddfa and Pen y Fan. Always check the latest mountain conditions before you head up, especially in the dark, and read our safety guidance first.
Were you out on 22 September, or do you catch the next one? Tag @weatherduckuk on Instagram and we might feature your photos in a future post, always with credit and only with your permission.
Thanks to Neil Hollis, Snowdon Mountain Railway and DataCymru Ltd for the photos.