Let It Snow
Silly little mod that adds snowfalls in game using 6 randomized snowflakes that drift/spin while they fall down. You can configure how much time the addon should wait between snowfalls as well as the density of the snowfall, includes randomizers for most options for those who don't want it to simply be static every time. If you are crazy (or bored!) you can also set things like how long it should take to drift, where snow should come from or how far a drift should go.
Snowflakes from Bryne, the best person in the world.
Command line: /letitsnow (/lis) to open the configuration, /snow will let you manually trigger a snowfall.