。
I got caught in a sudden evening shower.
Literal
Evening-shower [with-に] encounter-[polite-ました].
A minimalist polite report of being caught in an evening shower. Note the kanji choice: 遭う with 遭 (encounter, usually negative — accidents, bad weather, trouble) rather than 会う (meet, used for people). Learners often miss this distinction because both verbs read あう, but the two kanji split a key semantic line: 遭う is reserved for unwelcome encounters, perfect for a sudden 夕立 ('evening shower').