So says University Park on their website:
City Ordinance prohibits the use of automatic sprinkler systems when the temperature is at or below 32 degrees. In addition to conserving water, this measure is intended reduce the likelihood of vehicle and pedestrian accidents caused by runoff that freezes on sidewalks, streets and alley surfaces. Property owners who are responsible for these dangerous conditions are subject to Municipal Court fines.
No one likes to slip and fall on some mysterious ice. But even if it was in the 40s this morning, we probably won't see frost until February. Either way, keep an eye out for your sprinkler systems as the winter months roll in.