based on past years they do the last 2 weekends in May and the first 2 in June - so May 22nd weekend (which is also Memorial Day weekend) is very likely.
That said - this year they did 5 weekends (probably due to the fact that one weekend was split between May and June). I am hoping they do it again next year and that May 15th is the first weekend! If I was completely honest I would hope they'd do SWW for all of the weekends in May and June (to spread the crowds out a bit) but I think that's fairly unlikely!