Social media sometimes carries questions like: “I want some good views from Snowdon. What would be a good month to come?” Or “I’m coming up in September [three months away]. What will the weather be like?” Many people too plan a date well in advance and just assume good conditions: “It’s my birthday on 3 April so we’re going up Snowdon.”
Now then, although we can make generalisations about the climate, namely that June will be warmer on average than December, we all know that on a day-to-day basis it’s impossible to predict the weather more than a few days in advance. Contrary to the usual or likely pattern, sometimes high summer can throw appalling weather at us, while a day in the depths of winter can prove glorious.
Take the two pictures below, for instance. The first was taken on December 10, 2021. The second picture was taken just six days later. On the earlier date, no-one stood a chance of getting anywhere near the summit without crampons – the whole upper 80m of the mountain was a complete ice sheet, and below that height there was a serious depth of snow. Less than a week later, it had all gone and anyone could have walked up in summer gear (not that it was as warm as summer, but you get the idea).
Last winter, at one point there was a good depth of snow on the mountain, right down to Pen y Pass, but then it suddenly turned mild and wet and the whole lot disappeared within 48 hours. That kind of thing isn’t unusual.
Winters on Yr Wyddfa (Snowdon) can be strange, and February and March can certainly be strange months. Most times though, you have to expect full winter conditions, but I recall a day in February where a T-shirt is all I wore at the summit. Yr Wyddfa is indeed a fickle woman.
The same applies to other phenomena like amazing sunrises or temperature inversions. People sometimes ask when would be a good time to go up Snowdon to catch either of these? How long is a piece of string? Again, particular weather conditions lend themselves to these phenomena, and may be predictable over a very limited number of days (i.e. current conditions continuing), but other than that you just have to take your chances and look closely at the forecast. (You’d be surprised how many people walk up Yr Wyddfa to catch the sunrise, when it’s patently clear from the forecast that the mountain will be covered in low cloud and there won’t be any kind of visible sunrise.)
Of course, you can improve the odds of booking good weather on Yr Wyddfa by learning a bit about climatology and basic meteorology (e.g. high pressure patterns, and that the amount of cloud cover and its height will affect sunrise views) or by checking the forecasts. No-one has a crystal ball that can predict accurate weather long distance, but the forecasts we have are pretty good for short range, and it’s disappointing to encounter walkers who have optimistically travelled long distances for conditions which just aren’t going to happen.
I admit that some of us are privileged when it comes to being able to pick good weather on Yr Wyddfa. Living just a short distance away, when I’m not working on the mountain (and unavoidably having to take whatever weather comes), I can totally pick and choose my days at short notice. Ideal.