Save Mount Diablo sponsors many spring and fall schedules of events on the mountain, Spring on Diablo and Autumn on Diablo, as well as many other special events, including its anniversary event, Moonlight on the Mountain; Four Days Diablo, a trip on the Diablo Trail; the Mount Diablo Challenge, an annual hill climb to the summit with more than 1,100 cyclists each October; and the Mount Diablo Trail Adventure, combined 10k and half-marathon hikes and runs.