My Jeep won't start or even crank if it's hot outside and the windows are closed.
If a cloudy or rainy day, starts fine every time. Only fails to crank or start if
inside of care becomes hot. Engine never overheats.
Sounds like you have a bad ground connection which would actually be under the hood. When it's wet the water becomes the conductor, but when it's hot and everything is dry the corroded bad connection causes your problem. I suggest it's under the hood because there hopefully isn't any water inside of your car to conduct the electricity/ complete the ground.