What is it?
Prepositions of time show when an action, event, or situation happens.
The most common prepositions of time are in, on, and at.
- in is used for longer periods of time.
- on is used for days and dates.
- at is used for exact times and specific points in time.
Examples:
- We travel in July.
- The meeting is on Monday.
- The train leaves at 8:30.
When to use
Use in with:
- months: in January
- years: in 2026
- seasons: in summer
- centuries: in the twenty-first century
- parts of the day: in the morning
- longer periods: in the past
Use on with:
- days of the week: on Friday
- dates: on August 3
- special days: on my birthday
- a day with a part of the day: on Monday morning
Use at with:
- exact times: at 7:00
- mealtimes: at lunchtime
- specific points in time: at midnight
- holiday periods: at Christmas
- the expression at night
Structure
A preposition of time usually comes before a time word or time phrase.
subject + verb + preposition of time + time expression
- She works in the morning.
- We have a meeting on Tuesday.
- The shop closes at six.
Using in
| Use | Example |
|---|---|
| month | in September |
| year | in 2025 |
| season | in winter |
| century | in the twentieth century |
| part of the day | in the afternoon |
| longer period | in the future |
Using on
| Use | Example |
|---|---|
| day | on Wednesday |
| date | on July 15 |
| special day | on New Year’s Day |
| day and part of the day | on Friday evening |
Using at
| Use | Example |
|---|---|
| exact time | at 9:30 |
| noon or midnight | at noon |
| mealtime | at breakfast |
| night | at night |
| holiday period | at Easter |
Position in a sentence
The time phrase can appear at the beginning or end of a sentence.
- We have class on Monday.
- On Monday, we have class.
Do not normally use in, on, or at before these words:
- today
- tomorrow
- yesterday
- last
- next
- every
- this
Examples:
- I saw her yesterday.
- We are leaving next week.
- He works every Saturday.
Examples
- I usually exercise in the morning.
- She was born in 1998.
- We go skiing in winter.
- The appointment is on Thursday.
- His birthday is on May 12.
- They arrived on Friday evening.
- The film starts at 7:30.
- We usually eat dinner at six.
- The streets are quiet at night.
- I will see my family at Christmas.
Exceptions
Use at night, but use in the morning, in the afternoon, and in the evening.
- I sleep at night.
- I work in the evening.
Use on when a specific day comes before a part of the day.
- on Monday morning
- on Saturday night
British English commonly uses at the weekend, while American English commonly uses on the weekend.
Do not use a preposition before last, next, this, or every.
- last year
- next Monday
- this evening
- every morning
Common mistakes
-
Incorrect: The meeting is in Monday. Correct: The meeting is on Monday. Explanation: Use on with days of the week.
-
Incorrect: She was born on 2001. Correct: She was born in 2001. Explanation: Use in with years.
-
Incorrect: The train leaves on 8:00. Correct: The train leaves at 8:00. Explanation: Use at with exact times.
-
Incorrect: I study at the morning. Correct: I study in the morning. Explanation: Use in with the morning, afternoon, and evening.
-
Incorrect: We walked in night. Correct: We walked at night. Explanation: Use the fixed expression at night.
-
Incorrect: I will call you in Friday evening. Correct: I will call you on Friday evening. Explanation: Use on with a specific day and part of the day.
-
Incorrect: We travelled in last summer. Correct: We travelled last summer. Explanation: Do not use a preposition before last.
-
Incorrect: She works on every Monday. Correct: She works every Monday. Explanation: Do not use a preposition before every.