When you go climbing here, remember that thunderstorms blow in in minutes at altitude. And when you are working your way through a sea of rock, a human makes an excellent lightning rod. Every year a few people get hit. Most live, but some... So we recommend that you do everything you need to, to be headed back down the hill before noon, some days even earlier.
Another thing to be aware of is altitude sickness. For some folks, a climb will go a lot easier and safer if they sleep at 10,000 feet or better the night before. Never underrate the beneficial effects of acclimation.
Rain gear, sunblock, hat, bandaids, gorp, lunch, lots of water, sunglasses, a compass, USGS map, survey tape, trekking poles, a good camera, binoculars, and a cell phone (but don't count on it) round out what's usually in a backpack, especially if you want to maximize the joy, the wonder and the safety of the experience. One regular hiker puts it like this: "If I can drive to the bottom of the hill I take less, if I'm going deep in the mountains I take more. And I always check the long range weather forecast before I leave the house. I'm in it for the fun and a bit of adventure. I have come across people out there who didn't do any of this, and they were hurting."