The weather was very nice, not too hot or cold, we started from Mitchell canyon road, it said it is 7.30 miles to reach the summit from canyon mitchell road, so we thought around 15 miles, but we ended up doing almost 18 miles, we reached a couple of forks, and it had us go left or right on one for it said  summit higher level and it took us somewhere else, so we went back down, and took the road that said mount diablo summit to parking lot for the summit and it took us directly to there. The hike was very beautiful, my friend had a prior condition with her ankle and, while we were going up, she was struggling a bit, she was using her trecking poles the whole time, she made it to the top, than when we were going down, we thought it would be okay, but her ankles were really hurting her, but we hit night fall, so we had to keep on going, because of the animals so it got king of scary, but still a great experience,   My friend Connie, said she should have defenitely were her ankle hiking boots, and some knee compressions, going down, was tough, I myself enjoy small difficult hikes, I was okay, didnt use the tracking poles and I was okay, had regular hiking boots.  definitely recommend the full long hike so beutiful the views are amazing.  When we got home are feet were swollen connie did have to take some inflammation pills, and she will be going to the doctor to check out her ankle.  But not regrets.