Here are some tips for staying cool in the high heat and humidity. Make sure if you are working outside to take frequent breaks. Drink plently of water, and eat. Avoid drinking too much gatorade, or powerade. The sugars in those drinks will actually dehyrdate you more. Have a mixture of half water and half gatorade.
Here is a link that debunks some common myths about Heat Stress: http://blogs.cdc.gov/niosh-science-blog/2011/08/12/heat-2/