My local California cherry report: Murray Family Farms from near Bakersfield in the San Joaquin Valley has been bringing cherries to our local farmers market for over a month now. It was a bit of an early start for them. Brooks and Rainiers were first. Bings have been there the last 2 weeks along with GG1s. This past week, Lamberts showed up and a few other varieties that I failed to take note of. I think they will be done soon, at least for the ones they bring to our market. I think they sell all their sour cherries at their farmstands or maybe larger markets like Santa Monica. Another farmer had them for ~ 3 weeks but is now done. He's also San Joaquin Valley, but a little further south.
The U-pick place I usually go to is near Lancaster, CA in the Leona Valley. Their first picking day will be this coming Friday, June 3. Brooks are always first for them, too, followed by Rainiers and then Bings.