Here's a really nice guide to year round turf grass irrigation in California:
UC Davis Lawn Watering Guide for CaliforniaThis divides the state into geographic regions and tells you how much water to apply per week with different water outputs, per region.
In addition to using this historical ET data to set up your schedules, with LawnCheck you can also set up additional weather based cycles so that if the season is unusually cool, less water will be applied, and if the season is unusually warm, more water can be applied.
If you live in California and you want optimal irrigation for your lawn, the information provided in the link above will be very helpful.
Jim
