Normally you would start repairing and seeding a lawn now, but in my opinion it's still too hot and dry to do so. I would hold off another week to see what the weather brings in the way of cooler temperatures and rainfall. However, there some things that can be done to prepare the lawn for seeding.
Eliminate crabgrass (which is still growing) and broad leaf weeds. This would be the first step in a fall lawn rejuvenation program anyway since you have to wait 2 to 3 weeks after this application before seeding. A combination spray such as Orthos' Weed-B-Gone Plus Crabgrass Control is perfect for this task. Due to the dry conditions, water the lawn a couple of hours prior to treatment.
You can de-thatch the lawn in preparation for over seeding. Water afterwards as this is a harsh procedure on the grass. Bring in topsoil to level off any dips in the lawn or areas where water pools.
Have your soil tested to see what the pH is and what nutrients the soil may be lacking. A good way to do this is to send a sample to the UConn Soil Nutrient Analysis Laboratory. We have pamphlets in our Garden Shop that give you all the instructions. If you need more immediate results, we do sell Rapitest Soil Test Kits which are easy to use.
Call or come visit Dr.Z to have the rest of your gardening questions answered!