As a lifelong resident (I am 50 years young) I can tell you that we have actually been getting snow more frequently as the years have gone on. I believe (and I am no meteorologist) that it is due to the increased humidity due to the increased population, combined with the fact that the old city was mainly lower in the valley than it is now. As the town has grown, more homes have been built in the higher altitudes. The center of town gets MUCH less snow than the outlying areas.

When I was a child, the answer always given was that it snowed every 7 years where it stayed on the ground. Now it seems to snow every 2-3 years where it sticks.

I do not believe that the temp has decreased, just that due to the factors above, we get more.