"It is raining and it is foggy."
Translation:Il pleut et il y a du brouillard.
And descriptive verbs with actual on-going weather processes, correct? For example: Il pleut, il neige: "It's raining, it's snowing".
There still seems to be some idiomatic preferences,, depending on the phenomenon. For instance, my inclination as a native English-speaker would be to say,il est venteux rather than il fait du vent because "it's windy" is definitely the much-preferred English way of remarking on the weather phenomenon, but idiom is idiom, and can't really be argued with.
"Il fait" is followed by an adjective: il fait beau, mauvais, froid, chaud...
"Il y a" is followed by a noun: il y a du vent, des nuages
"Il pleut", "il neige", "il gèle"... are verbs you have to use with the impersonal pronoun "il", like "it is raining, it is snowing, it is freezing".