雨が降ろうと晴れようと関係がない。

rain

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

to descend; to go down; to come down; to be handed down (of an order, judgment, etc.); to pass (of time); to surrender; to capitulate; (often in neg. form) to be less than; to be inferior to; to have the runs; to have diarrhea

if; when; and; with; particle used for quoting (with speech, thoughts, etc.); quoting particle; promoted pawn; indicates question (sentence end)

to clear up; to clear away; to be sunny; to stop raining; to refresh (e.g. spirits); to be cleared (e.g. of a suspicion); to be dispelled; to be banished

relation; relationship; connection; participation; involvement; concern; influence; effect; sexual relations; sexual relationship; related to ...; connected to ...

nonexistent; not being (there); unpossessed; unowned; not had; unique; indicates negation, inexperience, unnecessariness or impossibility; not ...; to not be...; to have not ...