We've traveled in up to 108 in the southern central valley of California. After that trip we decided to get cooling vests and wear them when it's over 95. They work well in areas without humidity. We don't go places with high humidity, but I've heard they're useless, since they work by evaporation. Don't get me wrong, when it's 100 you're still going to be hot, but it helps. About $30 on Amazon.