In, on, and at are prepositions of time. They are used to talk about when something happens. The difference depends on how specific the time is.
At → exact time
Use at for precise moments.
- At 3 p.m.
- At noon
- At midnight
- At the weekend (British English)
- The meeting is at 10:00.
- I wake up at 7 a.m.
On → days and dates
Use on for specific days and dates.
- On Monday
- On July 5th
- On my birthday
- We have a meeting on Friday.
- She was born on June 12th.
In → longer periods
Use in for longer periods like months, years, seasons, and parts of the day.
- In 2024
- In July
- In summer
- In the morning
- I was born in 1995.
- We will travel in August.
Important exceptions
- At night (not “in the night”)
- On the weekend (American English)
- In the morning / afternoon / evening
Key idea
- At → precise moment
- On → day or date
- In → longer period
