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

Thanks for all of your kind suggestions. I decided to take on the learning curve of winterizing it myself. The worst part being locating the required drains. I also had a difficult time finding a blow-out fitting, so I found a short piece of hose and installed a male air hose coupling on the other end. This worked well, so I am good to go.

Thanks again for sharing your knowledge. I look forward to learning more.