Winter Watering

[Needaclue]

How much water does a lawn need during winter, if any? Our temps are generally ranging from 40 to 60 degrees during the day and 20-40 degrees at night. I have an automatic sprinkler system. I'm watering areas served by stationary sprinklers 10 minutes and oscillating sprinklers 15 minutes, once a week. The horsehocky about "your lawn needs 1 in per week" doesn't work for me during summer. I've never read what is needed during winter. Can anyone give me a clue?

Just moved in in 2005. First time I've dealt with a lawn. We don't get snow. We have had little rain. Cheers!