Learn this pairing: in + a longer time, like a month, a year, or a season.
in = a month, year, or season
Amina's birthday is in May.
The school opened in 2024.
It's cold in winter.
Not "Amina's birthday is at May." — say "Amina's birthday is in May.". A longer time like a month takes in, not "at".
Try it: Amina's birthday is ___ May. (in / at / on) Answer: in — A month takes in: in May. "at" is for a clock time, not a month.
on = a date
Learn this pairing: on + a date. A date is a month with a day number: on May 3.
The art show is on June 6.
My class starts on September 10.
The party is on the twenty-first.
Not "The art show is in June 6." — say "The art show is on June 6.". June on its own takes in, but June 6 is a date, and a date takes on.
Try it: Mateo: Write it in your book. The art show is ___ October 4. (on / in / at) Answer: on — October 4 is a date, a month with a day number, and a date takes on.
at, on, or in?
The three time words go with three sizes of time:
at + a clock time: at seven o'clock
on + a day or a date: on Monday, on May 3
in + a month, a season, or a year: in May, in winter, in 2024
The doors open at eight-thirty.
We have class on Tuesday.
Her birthday is in May.
Not "Her birthday is on May." — say "Her birthday is in May.". May 3 is a date and takes on, but May on its own is a month and takes in.
Try it: The party is ___ Saturday. (on / in / at) Answer: on — Saturday is a day, so it takes on: on Saturday.
Try it: Lani: When do the new classes start? Farid: They start ___ September, right after the summer. Finish Farid's answer. (in / on / at) Answer: in — Farid gives a month with no day number, and a month takes in. A date like September 10 would take on, and a clock time would take at.