Cy's right, it's fully doable in the summer, you just have to plan accordingly. I've posted a couple of times before that I did it in July, but carried extra water and a "Misty Mate". I used up two liters spraying cool mist on myself, but it worked amazingly well and I was cool to cold the whole time. I loved it.
Still, I'd really encourage you to think about Walt's suggestion. I did a loop around the top of the mountain last summer, and it was cool and the scenery was amazing. I also went down to Caramba, which had flowing water and no people, so I couldn't resist a refreshing dip. The water was a little cold

but very much appreciated at the time. If you haven't explored the upper trails, they're more than worth it, they're wonderful.
When are you going to be out here? Maybe a few board posters will be on the mountain that day and we can all say hi.
z