I agree with Steve on this with couple provisos. Everything depends on winter not making an encore. If we get a winter blast in April, the switchbacks might take longer to open, since the cables have a base of compacted snow already. If we have a very cold spring, it could move the opening through the cables into mid-June but a hot one might move it into May.
Weather is always a guessing game. All any of us can provide you with is what we have seen in the past and what we have seen this past winter in Sierra and SoCal mountains. My feeling on the latter is the melt is a few weeks ahead of last year. The last storm in 2012 was 3/18, this year it was a minor dump on 3/10.
As for gear, standard 3-season stuff for clothing...I've seen near freezing and mid teens at night this weekend in the Sierra. As for winter gear...you have to plan for the use of axe and crampons this time of year. Whether or not they are needed is another question. I do not believe this gear should be rented unless you have arrest and belay skills.
