The single preseason Half Dome day-hike lottery, open March 1-31, with results in mid-April.
Yosemite's own Half Dome permits page caps the trail beyond the subdome at 300 hikers a day (about 225 day hikers). Day-hiker permits go by lottery on Recreation.gov: one preseason lottery, March 1-31 with results in mid-April, and daily lotteries two days before the hike date, midnight to 4 p.m. Pacific, from expected under-use and cancellations. We alert when each opens.
Updated , checked by hand against the target's own page.
Watched from nps.gov, the target's own public page — not a reservation system we poll.