Thus a sure fire way to adapt to hot weather is simply to ride in it. It's best to alternate days in the heat at first. This will help dilate your sweat and make you sweat more easily. And eventually, you'll get used to the heat. Along the sweaty way to adaptation, though, there a few things we can do to make life a little easier.
Hydration is the bottom line in athletic performance.
Even a small decrease in blood volume due to dehydration can cause your blood to sludge and thus encourage poor oxygen circulation, cramps, nausea, dizziness, and eventual physical shutdown. Put your water bottle in a wet sock and let Mother Nature keep it chilled for you. It's like riding in a refrigerator even on a scorching day. Sew a terry cloth towel in a pocket shape to the back of your cycling cap and fill it full of ice. Finally, wear light or white colored clothes to reflect the heat.