(as) hot as Hades

Extremely and uncomfortably hot in temperature. ("Hades" is another name for Hell.) On summer days in Texas, when it's hot as Hades outside, there's nothing quite like a tall glass of sweet tea. I hate working in the theme park during the summer. It gets as hot as Hades in those ridiculous costumes they make us wear. We need to get the air conditioner fixed as soon as possible because it's going to be hot as Hades this week.