From KState Turf-

There has been a little bit of relief from the high air temperatures, with highs in the 80's on some days and lows in 60's and even 50's once or twice in some areas of the state.  However, daily maximum soil temps are still high, in the mid to upper 80's.  For cool-season turf, roots don't grow at all when 4-inch soil temps are greater than about 77