Dunno, but I wouldn't want to live in London any more. And that's not even just for the weather!
Let's face it 1 or 2 Deg C makes all the difference. Either it falls as rain, and if it does snow, it lasts less long. Pandemic makes no diff, I would say its the sheer (over)population of the area in terms of dwelling that b_uggers your chances up -- so situtation very normal. If you want decent chances of Snow, do a 'me' and get the hell out of London!