Summers in the Sierra are warm and dry. Yosemite receives less than five percent of its annual precipitation in summer, mostly as rain from thunderstorms. Daytime temperatures in Yosemite Valley sometimes reach 100°F during summer, while nights are cool. Temperatures in Tuolumne Meadows (8,600 feet) in mid-summer are usually in the 70s in the daytime and in the 30s at night. Though skies are usually clear, thunderstorms can be a daily occurrence in summer afternoons. Usually forming at higher elevations, thunderstorms form suddenly and can provide intense but brief downpours, lightning, thunder, hail, and gusty winds. Typically, by nightfall skies are clear once again.