That's good you're not cutting the grass short. Especially during the summer heat, turf does better when it is left a little long. It could be that despite your daily irrigation, the turf is going dormant for the summer. Cool season grasses rest during the hottest, driest weeks in the summer. Soon after the cooler fall weather comes and the turf starts to green up again, cut your watering to every other, and then every third day. Then next spring program your irrigation system to run every third or fourth day. By increasing your watering intervals, you'll encourage the turf to root more deeply. Deeper roots means your lawn will respond better to the irrigation next summer and you'll be able to avoid summer dormancy.