Hi Mark
I too carry water with me during the summer. The best thing to do, is to put a bottle in the freezer overnight. Not only does it cool you off when drinking it, you can also put the frozen bottle on your wrists to cool you down. Another trick is to wear sunglasses. My eyes are very sensitive to the sun, and I feel that when I squint alot, it brings on a tension headache. Luckily, my office is fairly cool, but when it does get a little warm, I will go to the restroom and run cold water on myself.
It's funny most people get seasonal depression during the winter, not me, I feel so trapped during the summer. I stay in air conditioning as much as possible. Anything above 70 degrees makes me feel uncomfortable. My friends call me a vampire, I try to do what I can when the sun goes down. If only they could experience what I feel for only one day. (They have no idea about my panic attacks) The summer cannot end soon enough for me. Bring on Autumn!