Get some window tint, gents. That will keep the internal temperature down even in the hot sun. Use the darkest that's legal in your state, and get as many of the windows done as is legal.
Here in Texas, I had everything but the windshield covered with 35% VLT SunTek Carbon XP (including back window and glass roof). Internal temperatures are at least 20-25 degrees F lower than before.
I think in some other states, the VLT (visible light transmission) percentage may be allowed to be lower, but check before you have it installed. Also, some states prohibit tinting driver's and passenger's windows and/or rear window, you can only do back side windows.
I have never had window tint on any of my previous cars, the Model 3 is the first one I've had done, and I'm astonished at the temperature difference. Even when driving, the interior of the car is less stratified while the A/C is on, with a lot less heat near the roof glass.