One of my favorites. We stayed in a Curry Village cabin and left around 5am under headlight. We summited the Half Dome around 1pm, mid-September hike. Cables are tough, it then agiain the sub dome is too. We hiked up along both of the major falls and back down the JMT.
I've climbed Half Dome twice, both times on July 4th (in 2017 and 2018). To prepare for the hike, I did a lot of stairs at the gym and outside, in addition to hiking long distances where possible (I was living in Alabama and had limited access to long hikes with significant elevation gain). I started with doing about 50 flights of stairs at once and ramped up to 250 flights over the course of several weeks. I felt more than physically prepared for the hike, including the difficult granite stairs at the base of the Dome.
For both hiks, I left the Pines campgrounds around 4:30 a.m. My group decided to take the John Muir Trail up instead of the Mist Trail because it's gentler on the knees and not as cold (the Mist trail can be cold if you get wet in the dark). We summited around 9 a.m. and spent several hours on the Dome enjoying the view and exploring all over. We took our time coming down, soaking our feet in the streams and taking in the views, knowing that whatever we would be doing in camp at the end of the day was going to be less interesting than what we would see on the hike.
(Additional preparation: you need permits for Half Dome. The Rangers will turn you away if you don't have a permit for each hiker. However, I have seen several folks get permits by waiting at the check point at the base of the granite stairs for parties that have extra permits, but this is not a guarantee.)
I’ve hiked half dome three times. My favorite was a full moon hike where we left lower pines around 9pm. Needed a head lamp for the first couple of hours but then it was bright enough without one the rest of the trip. It was by far my favorite for several reasons: no crowds going up the cables, cool weather, amazing sunrise.
For any type of half dome attempt you need to train. Focus more on endurance and less on speed. It’s a long day with steep ascent. Depending on your skill and fitness level you could be out there 12+ hours. What people don’t realize is that going downhill is incredibly straining as well. It helps to incorporate both climbing up and down motions in your workouts. If you can get out hiking with elevation gain that is ideal. During the week get on a stair climber. Try to build up to 30 mins, then 45, then an hour.
Bring plenty of water, snacks, and grippy gloves for the cables, sunscreen. If they still allow the night ascent you will want to pack warm clothes or even a light sleeping bag for the summit. It can get pretty cold while waiting for the sunrise.
secure a permit. I’m not sure if one is required now for a night hike so I would check on that.