The biggest time for fowl pox where I live is aug - oct usually. Temps here that range between 70-40 would be right in the middle of that time frame. I suppose it might depend on what your plans are for the bird to be dubbed.
70 degrees and you still have plenty of mosquitoes around.
Birds heal just fine in the cold.
I usually dub them when it’s 40 - 50 for the high and lows in the 20-30s. I don’t think it matters much as long as it’s not real hot. Blood flows slower in the cold so slightly less bleeding.