Your grass appreciates a higher mowing height during the hot summer months. Consider bumping your mower setting up a notch to leave your grass at the taller end of this range for your type of grass. (These suggested heights are after you mow):
2-1/2 to 4 inches for Bluegrass, Ryegrass and Fescue
2 to 4 inches for St. Augustinegrass and Bahiagrass
1 to 3 inches for Centipedegrass
1/2 to 2 inches for Bermudagrass
3 /4 to 2 inches for Zoysia
Then around September you could drop down to the lower end of the range for your grass type.
By the way, if you are not sure of your grass type, click here for a handy Grass Identifier tool that narrows your choices down by your zip code. You can then create a lawn care plan using this tool for your very own lawn.