Visiting in Summer
Areas to visit: All areas of the park are usually accessible by car by late May or early June, although services along the Tioga Road often open a bit later in June.
Weather: Warm to hot, with occasional rain (usually as afternoon thundershowers, especially at the higher elevations).
Fire & Smoke: Hazy or smoky conditions may occur during summer. This may be due to fires in the region or in the park. Lightning-caused fire occurs naturally in the Sierra Nevada. In some areas, the park may have prescribed fires to mimic natural fires to promote forest health and reduce the risk of larger fires. Additionally, accidental and arson fires can also occur, but firefighters typically attempt to suppress these fires immediately.
Rivers & Waterfalls: Most of the water flowing in Yosemite comes from snowmelt in the high country, so runoff decreases during the dry summer. Peak runoff typically occurs in May or June, with some waterfalls (including Yosemite Falls) having often only a trickle or being completely dry by August. (View a webcam showing Yosemite Falls to see current flow.) Other waterfalls, including Vernal, Nevada, and Bridalveil, run all year; however, their flow can be very low by late summer.