Hosmer Lake is fishable in the morning from dawn to about lunch in the Upper Lake but PLEASE watch water temps carefully and be careful with the fish handling by keeping them in the water even for the release. Damsel Nymphs, Callibaetis Nymphs, Scuds, Water Boatman, CB Cate, Soft Hackles, Watermelon Leeches and Red Chironomids.
The Lower Lake is likely too warm to be safe to fish. You can check the temp and decide, but watch that carefully.