Stay hydrated. Drink water.
I do golf course maintenance. Start early, off early. Riding home in the middle of the afternoon doesn't feel nearly as hot as edging bunkers, edging cart paths, or a hundred other manual labor tasks we do, all outdoors.
One thing I'm thankful for that I think helps deal with the heat is the shop is not air-conditioned. Another thing that I think helps is we don't run the ac at home.