Ive been in february a few times on vacation. I come from vancouver, and while its not the arctic north, its pretty much a constant 45 - 50 in early months of the year. LA at that time is much warmer comparatively and I usually wore shorts and a t shirt during the day and was fine. It did rain some trips a bit, but never seriously, drizzle and this odd fine misting rain we'd never get here (it only pours).
I really like it in february but the thing that I dont like is the reduced hours and the fantasmic / firework schedule. If you wnat to see either you have to be there on a weekend and if it gets cancelled due to weather, you're left without much recourse. Try and schedule to see it the earliest possible then if its canelled you can try again the next night.