Winters in Yosemite are relatively mild since Pacific storms bring in mild air. Snow begins accumulating on the higher peaks as early as September, but not in the valley until after Nov. 1. Snow in the valley rarely is more than two feet deep, although as much as five feet have been on the ground. Yosemite's famous waterfalls are at their fullest in spring when snow is melting. May and June are the best times for viewing the falls.
Mule deer migrate up the slopes as the snow melts.
Black oaks in Yosemite Valley begin to leaf out in April, the dogwoods bloom in early to mid-May and western azalea bushes bloom in late May and early June. Summer is warm and dry with less than 5 percent of the year's precipitation. Daytime temperatures in the valley sometimes climb above 100 degrees but nights are generally cool. Even in midsummer, temperatures in Tuolumne Meadows, at an elevation of 8,600 feet, are usually in the 70s during the day and 30s at night. Sudden thunderstorms sometimes bring dramatically changing clouds, intense but brief downpours, lightning, hail, and gusty winds.