I don't go anywhere when it's hot. Nothing makes my MG worse than the heat. A few years ago this August, we had record breaking temperatures and our air conditioner went out for those three days. I felt weak and sick, but was coping. The third day was a Friday and VERY suddenly I felt like my life was leaving my body. A feeling I never want to experience again. The next thing I knew, it was Sunday morning and I was in the ICU. I had gone into a crises, my husband called an ambulance and I have no recollection of what happened after that...which is just as well. So, my point is, please be very careful when in the heat and as soon as you feel uncomfortable or start to feel weak go to where it's cool...don't wait.