I would like to add a bit of clarity here, if I may:
AZ probably does have higher daytime temps, by a degree or two. (AZ = 104, TX = 102?) TX, however, easily has OVERALL higher temps, for far longer through the year. While AZ quickly cools off in the evenings, TX can be 90 into the night... AZ gets cooler weather much earlier in the year, and stays cooler much longer in the spring.
I ran my home A/C on both Christmas Eve & Christmas Day. My neighbors kids played outside on Christmas morning in a swimsuit, squirting water on himself with a garden hose. This scene did not happen in AZ in December, I can promise you that.
TX is an extremely harsh environment for cars and oils...