We were there the weekend before Labor Day. On the water by 6:15am Saturday, and 6:30am Sunday. The water was really nice until about 9:30 Saturday and 9 Sunday (much later than we expected). After that, it becomes a game of survival. We were there with (3) families and the riders knew you had to dawn patrol or forget it. For everybody else they still had fun hanging out on the water during the day.
Can't beat the house rental on the water thing Tulloch has, but the summer weekend water sucks. Much better off at a bigger lake (Don Pedro, Melones, Shasta, Oroville) on houseboat