How cold does it have to be to winterize the RV?

A month is a long time with the weather turning. I'd drain the water heater and put a gallon and a half of rv antifreeze through the water lines. I winterized mine today took maybe 15 minutes with me pumping the antifreeze and my wife talking to me on the phone opening each faucet till the pink comes through. I use a hand pump bought from Campingworld.