These were the decision dates last year, so expect them to be similar for this year:
Campus: Freshman.
Riverside: Early March (rolling thereafter)
Merced: March 4 (rolling thereafter))
Irvine: March 16 (rolling thereafter)
Santa Cruz: March 15
Davis March 11
Santa Barbara: March 21
San Diego: March 11
Los Angeles: March 18
Berkeley: March 24