Question
In May, my lawn looks great.  But by July and non-stop sun with little rain, it turns yellow and into thatch.  I use Scott's premium sun & shade seed but it still burns out.  Any suggestions would be appreciated.

Answer
Lets start with the basics David-
               First how do you water your grass? Sprinklers and irrigation systems work all right, but I prefer to use soaker hoses. Water everyday until you see water running off the lawn, then shut it off, once the water is running off the lawn it is no longer being absorbed by the soil. If you want you can also do this with sprinklers connected to a hose or your irrigation system, but I don't like them because they lose around 30% of the water to evaporation before it hits the soil. The main thing here is that it gets watered well and that will help to rinse the chemicals out.
                Second thing is let your grass grow! When your grass grows, the roots are growing too, and that is exactly what you want. The roots reach down into the soil to where its cooler and there is more moisture from your watering, and after some time even if you forget to water for a while, and the surface seems dry, the roots will still be getting that moisture. Also when you let it grow and cut high, there is more surface of the blade to get the wonderful sun that the grass needs so much. Let it grow for about a month or so, and then only cut 1/3 at a time, even if it isn't all the same height. This will encourage the rest of the grass to "catch up" so to speak, and it will even out perfect over time.
                If you see that there are weeds growing (and I'm sure you will.) take about 15 min or so and get rid of what you can, by pulling them out. You don't have to do them all at the same time, just do a little at a time every time you mow .The more you let it all grow the easier it will be to spot them, and with the regular watering, your soil will be nice and moist so it will be so easy to get them by the roots.
                Eventually you will have a weed free, healthy green lawn that was even better than before, but it will take time, patience and some work. If you are dedicated to it you will get results and you will actually be doing less work because nature will be doing all the work for you. Before you know it all you'll have to be doing is pulling the odd weed mowing, and watering.
        I think this should get you started, and if you have anymore questions or just need clarification or whatever, you know what to do!

P.S. -Sorry it has taken so long to reply but I have had some work issues going on and have been working some pretty long hours last week.
    Ciao