So many people ask the question

My turf has large dead and yellow areas in summer but remains lovely and green in winter. what can i do?

99% of the time your irrigation system is not watering efficiently or effectively. These areas indicate a lack of water is reaching your grass. You need to correctly space the sprinklers and ensure the pressure is correct for each station. Once you have rectified the coverage issue, you will need to increase water to these areas until they return. Fixing these things will make your grass greener in summer.