California Parks open all year?

I am tentatively planning a trip to CA (have never been there!) and would like to go in January or February. Would like to hit the parks in and near LA. Are they all open? I would love to hit both Disney Parks as well as Universal and SFMM and Knotts, if possible. Thanks!

Yes, they are are all opened that time of year. Sfmm would only be opened on weekends, but all those other parks are opened everyday.

If you plan on going in January, I would also recommend (if time and budget allows) a trip up to the Santa Cruz Beach Boardwalk. I was there in January a couple of years ago, and while it was cold, there was no one in the park. They are only open for limited operation, but you can ride and ride all day long with barely any lines. The Giant Dipper should not be missed! I haven't checked if they have the same schedule for next year, but they should be open in January.