There is always a tendency to keep lawns short, maybe to mimic a golf course, or just a preference. Low mowing heights in the spring helps clean-up debris. Longer mowing heights in summer heat will better shade soil to conserve moisture, the longer the turf the deeper the root system.
Keep your mowing height at 2 1/2 to 3 inches throughout the mowing season. Lawns require approximately 1″ of water per week in order to maintain a lush green lawn, more during hot, dry periods. Return your grass clippings to the lawn to help recycle the nutrients, providing a green lawn for a longer period of time. Do not allow grass to clump and smother the turf.
Check the Web for your turf grasses proper mowing height.