Learn Italian: Non possiamo uscire: il tempo sta per peggiorare. - We cannot go out: the weather is about to worsen.

To say that something is "about to" happen in Italian, you use the conjugated verb stare followed by per and an infinitive verb. Here, we have sta (it is) + per + peggiorare (to worsen).

Does il tempo mean "the time" or "the weather" here?

It means "the weather"! In Italian, the word il tempo is used for both time and weather. The context of not being able to go out makes it clear we are talking about the weather in this sentence.

Why is it uscire (to go out) instead of a conjugated form like usciamo (we go out)?

Because it directly follows the conjugated helper verb possiamo (we can). When verbs like potere (to be able to), volere (to want), or dovere (to have to) are followed by another action, that second verb always stays in its infinitive (dictionary) form.

Is the verb peggiorare related to the word peggio (worse)?

Yes! Peggio is the word for "worse," and peggiorare is the verb form of it, meaning "to get worse" or "to worsen."