I was checking through the Trail Journals site and see that two
thruhikers left well ahead of the pack. Their schedule calls for them
to be at Kennady Meadows on June 4th.
In any case the journal author has already done a thruhike of the PCT
so at least he is an experienced hiker.
Here is the link to their journal
As of last week the snowlevel out of Yosemite Valley was at 6500'. So
out of Happy Isles you will hit solid snow just past the Falls.
It is warming up earlier than last year. So there is a combo of more
snow /earlier melt/ dangerous streams .
'My guess' would put a SOBO hike some time about the first week of
July for an experienced hiker.
Perhaps the third week of July for someone with less experience. Even
then you will be hitting snow on the passes and still have dangerous
In years where there is a lot of snow the actual trail is a stream in
many places. It is quite possible that your feet and footwear will
never be dry the entire trip. A lot of very strong hikers I met last
year with heavy boots and heavy backpacking socks were forced off the
trail due to blisters. So be prepared to take care of your feet.