After a three week course required for my major on electrical safety, I got my first real world test. I had always been warned from veteran hikers and countless safety tips on this website to know when to turn around, and today I did, about 100ft below the summit.
Three of us, Craig, Kodi, and I, left Golden, CO around 4:15 AM. We lost a little bit of time finding the road after we went too far south on 285 and also by having to stop and ask at the Mount Princeton Hot Springs for directions.
We parked about 2 blocks below the radio towers. Some 4WD roads you can get by with a car that has good clearance, but not this one. A low-clearance Subaru probably would bottom out.

Walking up the 4WD road
The sky was pretty clear as we began hiking up this 4WD road to the trailhead at 7:30

Kodi and the valley
We lost some more time as we went to the too far up the 4WD road (the trailhead is on the right side about 0.75 mi before you get to the top.) But we eventually made it to the unmarked unsigned trailhead and continued hiking up to the peak.

Beginning of trail

Peak mostly free of snow
Soon we noticed there was a good amount of bouldering to be done, and unintentionally deviated from the trail a little and ran into some rather enjoyable rock-hopping. Unfortunately, soon we saw some dark clouds beginning to form that were quickly traveling toward us from the west.

Dark clouds begin to form
Soon the sky is filled with some pretty dark looking clouds, but we continue up the trail not hearing any thunder. As we hike up the steep south ridge below the summit the clouds continue to darken and we start to get some hail. Soon we do hear thunder, but it is considerably far away so we continue on. However, the thunder gets nearer, and Kodi's hair starts to stick up on his head.

Kodi on final summit pitch
All this time we are getting more uneasy about continuing on, and got to a point where we could see the top about 100ft away from us. We had seen a Peyton Manning doppelganger a few times on the trail, and he decided to turn around. We saw about 6 to 7 hikers on the trail looking up to us to see what we would do. After a pretty loud and near lightning strike (just to the north of the summit) we decided to turn back, and many lower hikers with us.
One hiker proclaimed proudly that he was just going to "sprint up and bag the sucker" who we later learned also turned back about 10 ft from the summit after he experienced a strange headache and buzzing sound.
We scurried down the peak quickly and were happy with our choice after seeing several more close lightning strikes. To be honest though, we were disappointed to see things clearing up after we had descended about 1000ft. We briefly considered trying to go back up, but we had gone off of 3-5 hours of sleep and just wanted to go home.
The trip down again held some pretty fun bouldering sections for a good percentage of the trail. It's was all really enjoyable solid class 2 terrain, although we noted there were some places we could have tried some class 3 moves (chimneys and steep faces & such) had we been so inclined or were the weather better.

Craig on descent
We got back to the car by 1 clocking in at ~5.5hr. By the time we were driving away on the paved road the conditions were bright and sunny again on the peak
This was Craig's unlucky #13 and it sure seemed that if we had arrived 30 minutes later or earlier we would have been fine. We certainly had more than a few "what if's" on the decent concerning the delays in finding the peak.
----> Research the peak better beforehand. We changed to Princeton from massive the night before in hopes of better weather. I thought I knew the area better, but a better look at the route description and google earth would have saved us about 30 mins.
----> Know when to turn back. As disappointing as it is to not summit this might have been our biggest victory today.
----> Climbing mountains is unpredictable and conditions change fast. This trip is a perfect example of this.