I decided to set a limit for temps at around 40 degrees. Wind is my main determining factor on whether I will fly though. I flew this winter down around 30 degrees and it was rough on the finger joints. I like to play guitar and do so more in winter so I don't want one thing effecting the other. Also I have had my neck fused and the cold tenses the muscles in my neck and that leads to other bad reactions.
I did start to make a radio box to block the wind a bit so I could attempt colder weather and this is what I came up with so far.
Made it from Wal-Mart foam board, a plastic lid from a big box of blueberries cut to fit and it is currently sitting in primer waiting on motivation whether to bother finishing it or not.