Like others have said, its certainly possible. Each year plenty of people do it safely. But imo as a AZ native, you shouldn't minimize the number of people in this thread who have said that while it is technically possible, its not really fun. Hiking in the desert in midsummer is just plain unenjoyable for most people. Its not like hiking say in winter, where the challenge only serves makes the experience more memorable and epic in the end. Its really not all that fun. Every year people try it, driven largely because summer is their vacation and the only time they have to visit the GC, and end up regretting it. If you're like me, you may be hard to dissuade once you've got an idea in your head, but I would at least have some other, more summer-friendly options in my back pocket if I were you. The rim hikes, although touristy, are excellent in the summer, and Mt Humphries, AZ's tallest peak, is only an hour south
of the GC and is also a great summer dayhike.