What is the English equivalent of the Russian saying "my ears are curling into tubes"?

Solution 1:

I've been in hot saunas and steam rooms and I've never thought that my ears are curling into tubes or heard an expression like it.

"It's hotter than hell here" is what folks might say.

In the UK they may say "It ain't half hot in here" for some unknown reason.

I've never heard Kris' "so hot the hens are laying hard-boiled eggs" but I like it.