According to all known recent weather conditions, there should be no snow in California.
The climate there is too warm for snow to stick to the ground. In BeamNG, of course, it snows anyway, because BeamNG doesn't care what nature considers possible :)

Joking aside, this map has snow-covered roads (with reduced friction) and many other custom elements. Reduced friction on the roads may not be the most realistic, but it's really fun to slide and go into drifts that you normally can't do.