Quick answer: Irrigation schedules should change as weather and landscape demand change. A controller that uses the same watering frequency and runtime from cool spring weather through summer heat can either waste water or leave the landscape short of what it needs.
Spring
Start conservatively and account for rainfall. Check that the system itself is working correctly before increasing runtimes to compensate for dry areas.
Summer
Hotter, drier periods may increase landscape water demand, but coverage, soil and sprinkler type still determine how water should be applied.
Fall
As temperatures cool, irrigation demand often declines. Continuing a peak-summer schedule can create unnecessary runoff or saturated soil.
Rain and weather delays
Rain sensors and weather-based controllers can help prevent scheduled watering when conditions do not require it, but their settings and operation should still be checked.
See how weather-based controllers can save water and how sprinkler runtimes are determined.
