Martha and the Vandellas sing Heatwave. Here are other summer- and heat-related songs. Send me links to those I missed:
The Heat is On: Glenn Frey (From Beverly Hills Cop)
Summer in the City: Lovin Spoonful
Hot ‘Lanta: The Allman Brothers Band
Hot Fun in the Summertime: Sly and the Family Stone
Summertime Blues: Eddie Cochran.
In the Summertime: Mongo Jerry