I have heard the same information concerning rust that Meryl has - - that the temperature must be well below 32 degrees for a period of time before the rust spores are killed. In my case here in eastern Georgia, I would assume that once I get the dead leaves off the plants, there will still be some rust remaining. I had started removing leaves before this last wintery blast, so I will have to start over with the ones I had already done. If there are a couple of days with decent temperatures (55 F or better) and no rain (like today) I will start with my first spraying so maybe I can reduce the likelihood of an early outbreak. Fred is right, a couple of days of moderate temperature and the evergreens will start growing again. Rust doesn't reproduce well at the lower temperatures, but it can surely live through what we here in the deep south call "cold."
Larry