I would think that if it gets down to 35 at night the meat would get well chilled and could then handle a 50 degree daytime temperature if it is kept in a shady spot. But that would just be for maybe a day or two. If you are looking at several days, I likely wouldn't mess around with leaving a deer hang unless it was under 40 pretty much all of the time. Much easier to just cut it up and keep it in ice chests.