http://www.jimmys-adventures.net/hiking-half-dome-in-yosemite/
Hiking Half Dome, Yosemite
I’m going to be completely honest with you. If you do not hike half dome at least once in your lifetime, your life has been in vain. I’m sorry was that a bit strong? Maybe. But seriously, Half dome is just one of those hikes you DO NOT want to miss out on. I can’t describe it any other way than simply saying it is one incredible hike. One that everybody should experience in their lifetime.
Before I get into the actual hiking of half dome, here’s a word on safety, preparedness, etc. Make sure to read this if you’ve never hiked half dome. Hiking half dome is approximately a 17 mile round trip, with an approximate elevation change of 5000 Ft. I don’t think I need to tell you that’s a pretty intense day hike. First of all, you’re going to want to be in shape for this one. People of most levels of fitness can accomplish this hike, Let’s be real though, you’re going to enjoy it a lot more if your calves aren’t on fire, your ankles don’t hurt the whole time, and you’re not constantly out of breath. Secondly, be prepared! Eat a big high carbohydrate (low fat and low protein) dinner the night before, followed by a good solid breakfast the day of. Make sure to bring a good lunch with you and plenty of snacks. I prefer to bring lots of energy bars, like cliffhanger, etc. along with other snacks. Bring plenty of water. A camelback back pack with the bladder filled to the brim and two extra waterbottles should keep you going quite nicely. This might be more than you need, but it never hurts to be prepared A waterfilter or iodine tablets is also something I highly recommend. Never hesitate to fill up on water when you get the chance. And very importantly, use quality footwear.Make sure your shoes/boots are broken in and comfortable. Obviously dress appropriately for the season in which you go: shorts and T-shirt will be good for summer, along with a hat and maybe some sunglasses and sunscreen. Bring a flashlight! My little hiking party would have been up the creek without a paddle had I not brought my flashlight the first time I hiked half dome. It gets dark quickly! Also, bring toiletpaper, nature might call when you least expect it. And for everybody’s sake, bury your duty far off the trail, please 
. Lastly, there’s no substitute for common sense, so make sure you pack that too!
The trail to half dome starts out at the Happy Isles trail head. From there you will want to take the John Muir Trail east along the Merced river. From there it’s pretty easy to find your way. The hike to Half dome is filled with some gorgeous scenery, but there are a couple acceptional sights to see. Such as the waterfalls you will pass on the way. Although not super spectacular or anything, walking along the Merced river is very calming and just neat, I don’t know how else to explain it! My favorite part of the whole hike other than climbing half-dome itself is the switchbacks just before half-dome. They’re part hiking part rock-climbing. And obviously the best part is climbing half-dome itself. This will probably be the most strenous part of the hike for many as you’re going to have to use a lot of upper body strength to pull yourself up the cables. However anyone who is fairly physically fit shouldn’t have too much of a problem.
IMPORTANT: Make sure you check to see if the cables will be up before you go! Park rangers take down the cables when they deem conditions too dangerous to be climbing in. They should be open most of the summer of 2009. Also, watch out for thunderstorms. There’s been a couple of deaths on half dome from lightning strikes. Im sure there can’t be a worse place to be in all of Yosemite during a thunderstorm!
Try and leave early in the morning so you can get back before it gets too dark. Around 6 or so is a good time to leave. Of course you’ve got the longer days on your side in the summer months. Even so, I once left around that time and ended up getting back at 11 o’clock at night, Mostly because I was hiking with some rather inexperienced female hikers . And it probably didn’t help that we were all pretty sore from lots of bike-riding the day before. The moral of this story being, make sure you don’t do anything too strenous the day before.
For a bit more on yosemite and some other not so extreme hiking trails, check out: Hike hard- Yosemite
Yosemite half dome cable climb trip