We went over Mono Pass into the Fourth Recess over the holidays and skies were clear, except for mosquitoes! Tioga Pass was a little smoky. Echo summit was more so. I think if you stay east of or near the crest south of Tioga Pass you will be OK. It sure is bad for the PCT hikers. About 10 days ago I met several of the early starters who had reached northern Yosemite (Smeldberg Lake area). They are probably near or past Donner summit by now and into the thick of the smoke.