In reply to TD:
Late July would be skin, shredding, not, nasty and greasy in the Bishop Area - Happy Boulders especially. Buttermilk is OK after 6 when cool air descends off the mountains. Better is further north: Sherwin Platea, Bachar Boulders, Deadmans......but still hot midday....much better would be Tuolumne...
Other USA Summer boulderinng areas: Rocky Mountain National Park and some other high elevation CO areas.......and Squamish....
Some high elevation areas in SoCal could be good, e.g., The Tramway.
Better if you have a car or a friend with one...this is less of a problem in Winter as there are lots of boulderers about.
For Bishop: Oct til May/June for bouldering.
Is that phat enough for you Toby dude...?
Mick