Sunny and hot in the summer, but good, best climbing season is spring or fall. Usually large and big granite boulders provide opportunities for highballs, exploration, and FA's. Best swimming is done in Aug-Oct.
Drive into Kings Canyon NP and go till the end of the road. Bouldering can be found at Roads End parking lot, across the road from Zumwalt Meadows parking lot, and more boulders 1-2 miles up the Paradise Valley trail(Roads End). Boulders can be found in campgrounds and all over the canyon. Several pay campgrounds a few miles from Roads End or free camp spots in the Natl. Forest.