Hi, Yeah you are, the two sentences are equivalent. But most of the time if you speak french you'll choose the first one to talk about the weather. I guess that's because it's faster and easier to say :) For your second question, here the verb "faire" describes a state, so the adjective should stay an adjective ! EDIT: Indeed, "chaud" here is an adverb, not an adjective

A Facebook friend sent me some great examples of when adjectives become adverbs: http://bdl.oqlf.gouv.qc.ca/bdl/gabarit_bdl.asp?id=4648 I hadn't noticed this happening in English, but a couple of examples are: The flame burns hot. It weighs heavy on his conscience. So now I understand how the phrase is correct.

Actually in 'Il fait chaud', ‘chaud' is formally an adjective but functionally an adverb. I mean : the word keeps the form of the adjective ‘chaud' but syntactically it is definitely an adverb. Same thing in : -'Parler fort' : ‘fort' is an adverb in this context -'Voir clair' : ‘clair' is an adverb in this context -etc. Sometimes function can be independent from form. ‘Etre’ is a verb, but it can function as a noun with the same form (Un être vivant), ‘froid' is an adjective but it can function as an adverb (Il fait froid) or a noun (Je déteste le froid) with the same form.