Moto367, I think it depends more on humidity for me. I was walking around in AZ in over 100 degrees, I was not hot. I just had to keep pushing liquids. Then there was the other day when it was in the mid 90s and high humidity and I had to stop get out of the sun because I was not feeling good.
Sorry to say, but in my current shape....I am not riding in the humidity until I expect it to be 90 or below.