34 degrees here today. Like always, my work puts me up and down the highway. I always stop at a rest stop 30 M from home (n or s) and play. Rain or shine, snow or sleet. It does go out of tune a bit, but the violin (an ebay cheapo) stays in my car. so it is quite acclimated. I fold a micro fiber towel over the chin rest and away I go. I do let the bow stay in the car and not the case. I really never have a problem. My fingers to get cold but, I also have a set of fingerless gloves that keep me going 20 - 30 minutes.
If the violin gets wet, I wipe it dry and let it fully dry in the house when I get home, then back out it goes. its been out there over a year now. I think the strings don't last as long and the bow can get gummed up, but a little alcohol (not drinkable. hehehe) and it cleans the bow up nicely. I do that about every 6 weeks or so on that particular one.
"I find your lack of Fiddle, disturbing" - Darth Vader