Black magic, Texas heat, AC works like a champ. Tint your windows with good, pricier tint with heat reflective properties. Buy one of those windshield reflectors. I'm telling you, my car never gets all that hot, so my AC doesn't have to fight that hard. You may want to check for a leak. For about 40$ you can buy a diagnostic set at a Pep Boys. You can check for deceased pressure first, and then use the included UV pen to scope for leaks.