I don't envy those temps Hans, I like snow but only when cudled up against a heater with a hot cup of coco with or without a drop of booze
I think the snow theme would work on any theme, but sure on a dark theme it would be more visible, why not find or create a fire overlay ..if a screensaver can set tables/windows on fire then it should be possible to do to a forum too (I guess) ... but don't ask me how
BTW if I'm not mistaking you can replace the snowflake by anything you like.. santa hats, xmas trees etc etc