Every spring, plow crews cut Highway 120 out of the snowpack and the highest road in Yosemite comes back. There is no fixed opening date: the long-term average is the end of May, light years have opened in mid-May, heavy years run into June or later, and the park announces the date only days ahead. In week one the road is open but the services are not: no potable water, nothing to buy, no gas between Crane Flat and Lee Vining, and the famous high trails still under snow. The early season rewards drivers, photographers, and modest walkers.
The reliable early stops are Olmsted Point, Tenaya Lake's east beach, the Tuolumne Meadows pullouts, Pothole Dome, and Soda Springs. The full day-by-day version: the opening-weekend field guide. Current status: the Park Bulletin and the NPS Tioga Road page.