Cold weather means cooler temperatures, more oxygen in the air (unless it's below or close to freezing), and generally good attmosphere for the engines to run.

While I don't regularly run in cold weather, if you are running in freezing conditions, you might have to run a hotter glowplug to make the engine run properly.

I'd say go for it. I don't see a reason to hold back! Tower hobbies sells front wheel ski-conversion kits for the RC-10GT, so there has to be a reason for it!