I have 2 cats and they prefer staying in the garden but in the summer it gets about 122f (50c) so should I shave them or not? And if I did would it effect them badly

If you do shave them, and I recommend having it done by a groomer, remember to leave some on the very tip of their tail for insulation. Many people have their cats shaved in the summer, especially ones that get extremely matted.

I hope you mean trim, not shave. No outdoor pet should be shaved to the skin. Yes, some vets allow shaving of the stomach, but it's silly. Too much exposure to the sun can harm the skin, and the tiniest nicks can get infected. Provide shade, tons of water, and ways to cool instead.