Q: A simple question: what is the best time of the day to water an established bermuda lawn?

A: The answer is unequivocal: lawn watering is best done in the morning. This allows two things to happen: the grass blades dry quickly, before fungi can grow on them, and less water is wasted due to hot temperatures in the afternoon. Use catch cups to measure how much water your system applies and adjust it to deliver an inch of water once per week during the summer, allowing grass roots to dry a bit before the next watering.