Prepositions of time are used to describe when an event happens.
Here’s a quick guide on how to use in, on, and at:
1. In is used for larger periods of time:
• Months: in January, in October
• Years: in 2020, in 1999
• Seasons: in summer, in winter
• Centuries: in the 21st century
Examples:
She was born in March.
The meeting is in 2022.
2. On is used for specific days and dates:
• Days of the week: on Monday, on Tuesday
• Dates: on March 5th, on Christmas Day
Examples:
We’ll meet on Friday.
His birthday is on December 25th.
3. At is used for precise times and moments:
• Times of the day: at 5 o’clock, at noon
• Holidays and special moments: at Christmas, at night
Examples:
The party starts at 7 PM.
I wake up at dawn.