Although the extreme heat is now hopefully just a memory, most lawns are still extremely dry if they have not been treated to a watering regimen over the past month. There was nearly 3 inches of rain in July, but most of that came in the first week, and conditions have been drought-like since.
Some lawns are dormant, and some may be completely dead by this point. Asta Sadauskis of The Greenery in Godfrey says if your lawn is dead, September is a good time to re-seed.
She says after you spread the grass seed, let the rain drive it down into the soil. If you can get one good mowing on it before the first freeze, she says it should be strong enough to survive the winter.