You can also get weather stations that automatically adjust the watering program based on temperatures. Depending on which brand you have, you program into the controller what plants you have, soil type, precipitation rate of the sprinklers/drippers and it calculates how long each zone should run for based on temps, so it will give less when it's been cooler, and more when it's been hotter. They claim to save around 30% compared to a regular timed based program.