How did your lawn fare during the 100 degree temps?
Worst case scenario - You gave up, stopped watering, and lawn went dormant. Not the best option, but the lawn will pop right back. It is VERY important to get rounds 4 & 5 (fertilizer and weed control) on your lawn. Your lawn needs the nutrients to recover from the heat stress before it goes dormant for the winter. If lawns are not "fed and watered" before the winter, the results will be more weeds and a thinner lawn next spring.
Best case scenario - You fertilized and watered (30-45 minutes per zone every other day) during the extreme heat. You may have seen a little heat stress at the end of the 100 degree temps, but overall your lawn stayed green and thick. Great job!
Suggestions for Next Summer
1. Don't skip any of the summer fertilizers. Think of the recent Olympics. Maintaining a lawn is like playing any sport. Your lawn needs to be fed and hydrated properly during our Oklahoma summers if you want to "win the gold (green)".
2. Consider installing an irrigation system. As a homeowner, this was the BEST investment! It saves me so much time as I no longer spend most mornings/evenings moving the water hose. So easy to give different areas exactly the amount of water it needs. No worries when I go on vacation!

SEPTEMBER/OCTOBER - Overseeding & Aerations
Overseeding -- If you have bare spots in your yard due to an area receiving too much shade, possibly from large trees or other structures, overseeding with fesque would be a good option for these areas. We overseed in the fall as fesque is a "cool season grass" and this gives the new grass time to get established before the next hot summer.
Fall Aeration - Many prefer to aerate the lawn in the fall to assist the lawn in recovering after a hot summer. An aeration consists of removing small plugs of dirt to allow nutrients, air, water, sunlight to go directly to the roots. Cost - double lawn application price.
May Your Lawns Be Green and Your Weeds Be Gone