You can safely drive your RC in just about any temperature that you might see up there in the DC area, as long as you take some precautions in temps below freezing.
I have run my RCs in snow and ice with temps of near -10F with the windchill. The key is set up and how you take care of the engine.
Note, I would not break in an engine in freezing temps. I would only run if the engine has already been properly broken in.
As for some of the precautions, I always pre-heat my engine prior to priming and starting it. I do this with a hair dryer on the heat sink of the engine for about 2 - 5 minutes.
From there, start her up and run like you want.
When it comes time to stop, get the hair dryer back out and allow the engine to cool slowly by keeping the hair dryer on it...after a bit take it from hi to lo, and then to off. Gradual cool down of the engine will prevent damages from metals that might cool too rapidly and warp.