May 14, 2021- Yosemite National Park officials report the Half Dome cables will be up for the season on Wednesday, May 19, 2021
A permit is required to summit Half Dome. Most permits are available via preseason lottery, but a limited number are available every day, two days in advance. Additionally, all permits for May 19–May 27 will become available two days in advance. See https://www.recreation.gov/permits/234652 for details.
If you will be hiking to Half Dome, be prepared with several liters of water, good hiking boots, and a headlamp (with extra batteries). Be prepared to turn around if a thunderstorm appears possible. Stay back from the Merced River, which is running high right now. If you see a bear on the trail or approaching you, scare it away by yelling loudly, aggressively, and persistently. Always keep your food within arm's reach. Oh, and have fun!
NPS photo
Source: NPS