Learn French: Le temps était mauvais ; néanmoins, nous sommes sortis. - The weather was bad; nevertheless, we went out.

Yes, it serves a similar purpose by introducing the contrasting point or the reality that contradicts the expectation. You could even combine them to write, "Certes, le temps était mauvais, néanmoins nous sommes sortis." Néanmoins (nevertheless) is just a bit more formal than mais (but).

Why is there a semicolon before and a comma after néanmoins?

In French, logical connectors like néanmoins, cependant, and toutefois often follow a semicolon and take a comma when connecting two independent clauses. This punctuation creates a structured, formal tone, which is very common in written arguments.

Why use the imperfect (était) in the first half but the passé composé (sommes sortis) in the second?

This highlights how these two past tenses interact. The imperfect (était) sets the scene by describing the ongoing background condition of the bad weather. The passé composé (sommes sortis) is used for the specific, completed action that happened despite that setting.

Can I use pourtant instead of néanmoins here?