Check for insect or disease damage first. For instance google: grubs, bilbugs, or web worms. Check for lesions or powdery spores on the leaf blades where the brown transitions to green.
If you find no indication of insects or disease concentrate on moisture.. "rule of thumb": turf needs about 1" of water to remain healthy green. Applying a surficant can help water to break the soil surface and helpthe soil hold water. A cheap surficant is clear shampoo like baby shampoo or White Rain. Apply 3 oz./1000 sq ft using a hose end sprayer.
Applying an organic fertilizer like alphalpha pellets or even Milorganite to a lesser extent can help some by adding organic matter which has a high water retention, will slowly feed N, and act as an insulator.
Finally, as a last resort, mechanical aeration and extensive watering can be used for emergency resusitation, but this time of year may result in weed prolifferation.

What is your watering schedule? How often and for how long?

Is the turf a mix of varieties of grass?