English grammar: Prepositions of time

What this grammar point covers

Prepositions of time are words like 'in', 'on', and 'at' that tell us when something happens.

When to use it

Use prepositions of time to say when an event happens. Choose 'in', 'on', or 'at' depending on if you talk about a general time, a day/date, or a specific time.

Key forms

• 'in' + months, years, seasons, long periods (e.g. in July, in 2020, in the morning)
• 'on' + days and dates (e.g. on Monday, on July 5th)
• 'at' + clock times, specific times of day, holidays (e.g. at 7 o'clock, at night, at Christmas)

Examples

Tips

• Use 'in' for months, years, and parts of the day.
• Use 'on' for days and specific dates.
• Use 'at' for exact times and special holidays.

Exceptions and edge cases

• We say 'at night' (not 'in night').
• We say 'on the weekend' (US English) or 'at the weekend' (UK English).