Is it a low snow enough year for a late May trip above tree line in the sierras?

As you have observed, this is lining up to be a very thin winter for snowpack, so the trails may open up much earlier than normal. Typically the maximum snowpack depth is measured around mid-March, so that is a good time to start making estimates. Still, you can get fooled, and there will be a late season storm that dumps a lot of snow.

Last year, I had a trip planned for early June. During planning, it appeared as though the trails would be nicely open by then. Two weeks before the trip, a big storm dumped snow all over the proposed trail. Suddenly I had to think about ice axes and crampons and all that. Fortunately, the snow melted off in time so I was able to go without any serious problem. My point is that you can't count on anything.

Just suppose that your trails are free of snow by late May. Then what? There won't be many wildflowers out that early. Trail maintenance crews probably won't get out that early.

–B.G.–

If you want to hit passes, you may want to use ones that will at least have some traffic going through by then.

Pretty much all the JMT passes have been hiked over by then on a low snow season.
If you were planning on the Rae Lakes Loop, I would 100% go counter clockwise.

I did the loop the 1st weekend of May 2 years ago and it was just getting to the point where hikers were going over the passes.

By late May on a low snow year, there will be tons of activity in the sierras, at least bellow tree line.

Of course it could dump between now and then, but right now it looks to be about the same as last year. Last year I did several trips above 10,000 ft in May and conditions were closer to July of a normal year…ice axes used in a few spots going over the high passes but not much other snow.

Sounds like the safe thing to do is to just keep the trip to Pecos Wilderness so I just booked our plane tickets into Santa Fe today. Thanks for the help. I hope the Pecos gives us the big open mountain feel we are looking for.