What Month, Which Month
noun
You have what month - as in: what month is it? It's １０月, you fool. Get a job, hippy.
なんがつ
This is a jukugo word, which usually means on'yomi readings from the kanji, but 何 actually uses the kun'yomi reading here! And since 月 has two on'yomi readings, here's a mnemonic to help you remember this reading: What month gives you naan guts (なんがつ)? It's the month you eat so much naan that even your guts turn into naan! But which month was it again?
何月生まれですか？
What month are you born in?
何月に入学しますか？
What month will you enroll?
ハワイに行くのは何月でもいいよ。
It doesn't matter what month we go to Hawaii.