Usually a good bet, still, snow may still present a problem, either on the road in, or the climb itself.
Climbed these on more than one occasion. Beautiful scenery without a doubt. And there is that old cabin on the upper ridge of Little Sister, though this time of year it may be under 10 feet of snow.
Keep in mind that the NW portion of Little Sister is cliffy, very cliffy...just a FYI.