"It is hot today."
Translation:Fa caldo oggi.
There is no "tempo" in the italian construction (in fact, it can also be used to describe the temperature inside your office).
I'm not religious, but something that helped me with this when I took Spanish was that my instructor said we should think of the weather in terms of something people long ago would have attributed to god's control--basically asserting "He (god) makes it hot today." To be honest, I don't even know if that the actual evolution of how that phrase came to be--but it hardly matters, it is still a good memory tool if it helps.
When you get to a situation that you dont understand, that is a good time to looking for some grammar rules from somewehre else. I found them but i can't recall it and list it off to you.
Meanwhile you just have ot learn which ones are used before the noun and which ones after.
You are correct about fare. But that's not why he got it wrong. I put "e caldo oggi" and was marked correct. I knew I was supposed to use "makes" but couldn't remember it, so took my next best shot, and scored based on DL's metrics. He missed it because he said it's not hot today, and the goal was to express it is hot today.
So Duolingo accepted "è caldo oggi", but didn't do the same with my "c'è caldo oggi"??? It doesn't make any sense, "c'è caldo oggi" is totally correct, and moreover it's more commonly used than "è caldo oggi", at least where I live (Sardinia, a place where it's hot pretty often!).
You can't always translate directly. 'fare' is 'to make/to do'. In English, weather 'is'. In Italian, the weather 'is made/does ...', which wouldn't make sense to the English ear, but that's just how it is. Just like you wouldn't say "he has 30 years" in English, but you would in Italian. Imagine explaining how you can 'be' years/time to a speaker of another language!