After running in the sun your "leg" are warm, but you "fore"head" is very hot.
You don't really say something is "very warm" in English. Meleg has a bit a broader application, forró is literally "boiling".
Hmm, I would say very warm if something is on the verge of being uncomfortable, but OK, if forró strictly means boiling, then this makes sense.
Forró doesn't strictly mean boiling. Yes, it literally is boiling, but it is also used as hot in the everyday speach: A tea forró - The tea is hot.