V, have you climbed any of those peaks in the dead of winter?
Are you going to try an overnight, or just do a long day climb? The Whitney Portal road is "closed" several miles from Whitney Portal, but if there is no snow, people will drive around the closure. But there can be rocks and ice on the road, as it is not kept clear at all during the winter.
As for weather, there can be long dry spells ...or storms. It will be the luck of the draw. Don't even consider it if there is any level of stormy weather.