My old man made my first sledge when I was about 5, and I remember using it every year - it snowed by December most years, and often lasted until March, on and off.
I also did a lot of skiing in the late 1960s - no problems wondering if it would snow then either. I think it was in 1969 that we went to Aviemore late on in the season - late April or early May - went skiing in the morning, back down at lunchtime and it was warm enough for a swim in Loch Morlich in the afternoon!