I live in Miami, Florida ( the sunshine state) after my TT and RAI, I'm been feeling that when it's hot me energy go down . I excercise every morning, trying to eat healthy, but around 5, I'm tired. Now I on vacation on Washington , DC it's been freezing , 10 , 20., and I feel great like before the cancer. I walk a lot , eat great, feeling with a lot of energy, my poor husband it's telling me that he is exhausted . He can't believe my energy change? It's this normal?

I'm not sure about "normal", but I'm guessing it could be. If you're taking supression doses of Levothyroxine and your TSH is very low, you may be experiencing some more hyperthyroid type symptoms and you're internal body temperature could be elevated... so in the cold, you may feel more "normal", where as in the heat in Florida, it's just making you even hotter than you already are and draiing your energy. I'd suggest talking/asking you Endo about this. If you're not feeling well and have no energy, you may be in need of some medication adjustments.