Greetings from the similarly chilly midwest.
I coerced the kids out last weekend for an "End of Christmas Break" launch, temp about 25 degrees. It was my first cold weather launch in a long time.
Lessons learned:
1. The "wind-chill-factor" tends to be a lot more pronounced on your big empty launch range than it does in your garage, dress really really warm.
2. Plastic chutes want to stay folded when they're cold (frozen). Open each one and repack it just before launch (I figured this out by the 3rd launch javascript:smilie(':kill:')).
3. If there's no snow, the ground will be REALLY hard, so 'chute failures have an even greater impact (so to speak) than on a nice warm summer day.
4. Plastic parts get really brittle at 25º. We lost the nosecone from a SkyWriter (the little plastic attach point for the shock cord broke off on ejection), and a D to C combination on a Snitch shot the C sustainer engine up through the top of the engine mount (it still lit). Pretty impressive considering the booster was just masking-taped to the sustainer engine and had no direct connection to the rocket itself (I thought I had a good friction fit on the C but my hands were kinda cold, so who knows).
5. Motors, which I kept outside with the rest of our stuff, did just fine.
6. I broke no fins, but did loosen a few, which made me question whether the temperature played a role on the fillets (both white glue and epoxy-clay fillets came loose on hard landings). It may have just been the increased ground hardness, though.
7. Surprisingly, my little Estes Electron Beam launcher generated enough juice just fine, but if you've got anything with more power, I'd use it.
8. A Screamin' Mimi will do a really cool backwards glide (at about 35 mph) if the parachute stays completely furled. The whistles actually worked, however, in the cold dense air (we've never heard them on previous launches).
9. If you're bringing along the kids, bring plenty of candy, prep time between rockets is a lot longer with cold hands.
10. Whatever enjoyment points that got subtracted for physical discomfort were more than balanced out by the extra points we got back for stupid pointless winter fun (there was no snow, so I couldn't take the kids sledding).
Kid quote of the day: "Dad, this was a bad idea but I'm having lots of fun!"
Adult quote of the day: "Like, the whole Challenger thing went right over your head, didn't it?"
All in all, a great day. More rocket damage than usual but definitely worth it.