what time; when
Asks for a specific time of day, expecting an answer with hours and minutes. More precise than いつ.
今、何時何分ですか。
What time is it now?
次の電車は何時何分に来ますか。
At what time does the next train come?
いつ is a general 'when', not limited to clock time. 何時何分 expects a precise time answer.
Compound of 何時 (what hour) + 何分 (what minute).