You have what month - as in: what month is it? It's １０月, you fool. Get a job, hippy.
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?
What month do you start school?
When did it happen? What year, what month, what day, what time, what second was it? How many times did Earth spin when it happened?
What month were you born in, Ms. Tanaka?