I stopped in Needles, CA (on the CA/AZ border) to get gas once and it was 117*! I went into the store to pay for the gas and saw a homeless guy wearing a wool coat digging through the garbage. I said to the clerk" that guy's f'n crazy wearing that". She then informed my that I just walked across the parking lot with no shoes on.
Living on the beach, I never wore shoes at the time unless necessary. She then went on to inform me that once it hits a certain temp, it's cooler to wear heavy layers as it insulatiotes to your body temps...Learned something that day!