In hot weather it is not only important to take in more water and extra salt, but also additional potassium and other minerals. Potassium supplements in pill form might damage the digestive tract. A better idea is to eat potassium containing foods, which are basically all fruits and vegatables. Milk is also a good source of potassium. If you want to take potassium supplements, get capsules and open them up and dissolve them in plenty of water, or else get liquid potassium and disolve it in plenty of water.

Sometimes when there is hot weather there is also a thermal inversion, and the level of pollution in and around large cities might rise dramatically. If you are very chemically sensitive as I am, this might be a problem. with the warmer weather, if there is also humidity then mold levels in the air might be much greater than normal.