If no salt is used, and the frame is made with good quality steel, no worries. My '70 something bike, I rode 13 miles each way through Portland Oregon winters, not a spot of rust. I'm guessing you're not going to put fenders on a BMX bike, so as long as your ok with getting wet and no salt is used on the road, your bike will not rust out from under you.
I don't think it gets cold enough to get snow or ice in socal, so I'm sure there is no need for melting anything.
I have yet to wash or even wipe down the frame since the middle of last winter.
Last edited by Totaled108; 09-26-10 at 11:06 PM.