Best month for Southern California parks trip?

^How about that kick-butt little wild mouse? If it's anything like the one in Amarillo, TX, it's probably the best steel coaster in the whole of CA. Well, probably would be my favorite. Next to Revolution of course, covered in all those brakes, and shoulder gear ;)

January-Mid March.

Crowds will not be an issue, your biggest enemy will be rain. January-March is SoCal rain season and in the slightest amount of rain Knotts will shutdown all coasters. And if it is raining before park opening, the park will not open. Magic Mountain keeps most of its rides open, however if it is raining in the morning the park will not open. And if it starts to rain during the day both parks may close early.

Universal and Disney are open rain or shine.

What, it never rains in So Cal. Does it? ;)