The southeast buttress of Cathedral Peak, rising out of the high alpine meadows of Yosemite National Park, has long been considered one of the most classic climbing routes in North America. For some reason, during our younger days when we frequently climbed in Yosemite Valley and Tuolomne Meadows, we never got around to doing this route. Maybe we thought it was too crowded, or it was not difficult enough. I don't recall any specific reason we missed it, but I'm glad we didn't climb it in those days. It gave us a chance to savor this incredible climb in our wiser years.
It had been a little while since we climbed such a striking route. On the day before our climb we scouted out the approach and took a good look at the route from the base of the peak. When the sun rose as we hiked the next morning, the sky was deep blue and unmarred by a single cloud. The rock - oh, the rock. Perfect white granite. Friendly parties climbed below us, sharing encouragement. We swapped leads as we climbed up the narrowing face, heading quickly toward the summit block. High on the route, the line gets a little steeper. On top of the 5th pitch, I sat on a clean white ledge, one foot wide, in a sweet, crisp breeze, with the whole of the southern Yosemite mountains spread out before me. Karen quickly followed and then lead up the next pitch. We have climbed together for 35 years. That changes your perspective when you get a chance to climb again on cool, bright rock, in the high morning sun.
The southeast buttress is not a difficult route by any rock climbing standard (it's 5.6). But it is at high altitude, and it offers a full range of climbing techniques - friction, knobby face, chimneys, small cracks, flakes and a great summit. The rock is perfect white sierra granite. It couldn't be better.
The route's reputation makes it very popular. If you head out to enjoy the climb, plan to share the face with others. On a good summer day there may be 7 to 10 parties on the face. Our strategy was to get up early, hike up in partial darkness, and hope we were among the first parties to arrive for the day. We were at the base by 6:30 am, and had the face to ourselves - at least until the next party showed up 15 minutes later. Expect to spend 3 to 5 hours on the route, depending on your skill level and the crowds (we did it in 3 and a half hours). Although the route can be done in 5 long pitches, almost everyone we have talked with does it in 6 or 7 pitches. We did it in 7 - with 2 shortened pitches to reduce rope drag. There are multiple routes on the face which can be mixed together in infinite variations. I'd suggest you stay on the classic route if you can; it's a gorgeous line with some fine pitches.
The protection on the route is excellent, with no real need for any gear over 3 inches. A double set of cams to 3 inches and a few nuts are all you need. Bring some slings to keep the rope a little straighter on long zig-zag pitches (mostly on the upper half of the route). There are plenty of ledges for belays, making it easy to vary your belay stances if the route is crowded.
I suggest you use High Sierra Climbing, by Chris McNamara, as a reference. The brief section in this book which provides hints on the down climb from the summit is especially valuable. Also useful is the description of the approach trail, which deviates from the popular John Muir Trail and approaches the peak from the east.