A lot of them are played during the day, too. And the practices are probably during the day.
Look, guys and gals, the Super Bowl was played in 88 degree weather last February, during a period when there were heat advisories in So Cal.* I'm sure LA is less humid than Miami, but yesterday's conditions are not exactly unheard of... World Cups, numerous Olympics, the Australian Open, etc., on top of non-dome college football. Coach McD said that he told his players to start hydrating immediately after the Tennessee game. If so, they should have listened.
*https://www.washingtonpost.com/weather/2022/02/09/super-bowl-heat-advisory-california/