We were there last year from 12/20 - 12/23 and I do remember one night we were at Magic Kingdom to watch Spectro Magic and it was snowing on Main Street. I remember thinking how magical that was, the trip was a last minute trip because we had never been around the holidays and we wanted to see the Mickey statues.
So, there is always hope that you will show up on Main Street one evening and it will be snowing.