I actually do ok in the summers here, it just takes me a few days to adjust. If we have cool weather and all of sudden we have full blast summer heat, I feel pretty strange for a day or two but then I can handle the heat just fine.
The only problem is the weather has been fluctuating more, instead of being consistent, and I know its not just me because everyone else notices it. Its the fluctuations that get me, as apparently my body needs time to adjust.