What are Prepositions of Time?
Prepositions of time are used to say when something happens. The most common prepositions of time are in, on, and at. Choosing the right one depends on how specific the time is.
The meeting is at 3 PM.
Her birthday is on Friday.
I'm going on holiday in August.
1. Using AT
We use at for specific, precise times.
| Usage | Example |
|---|---|
| Precise Times | The class starts at 9:00 AM. |
| (hours, minutes) | I'll meet you at half past two. |
| Parts of the Day | We sleep at night. |
| (noon, night, midnight) | The stars shine at night. |
| Holiday Periods | What are you doing at Christmas? |
| (Christmas, Easter, New Year) | Families get together at Easter. |
| Specific Moments | He is busy at the moment. |
| See you at lunchtime. |
2. Using ON
We use on for more general times, like specific days and dates.
| Usage | Example |
|---|---|
| Days of the Week | I have a meeting on Monday. |
| We play football on Saturdays. | |
| Specific Dates | His birthday is on November 25th. |
| The exam is on the 1st of May. | |
| Specific Days | What are you doing on New Year's Day? |
| We'll have a party on your birthday. |
3. Using IN
We use in for the longest, most general periods of time.
| Usage | Example |
|---|---|
| Months, Seasons, Years | My birthday is in July. |
| I love to ski in the winter. | |
| The Beatles were famous in the 1960s. | |
| Long Periods of Time | This castle was built in the Middle Ages. |
| (decades, centuries) | Life was different in the 20th century. |
| Parts of the Day | I work best in the morning. |
| (the morning, the afternoon, the evening) | She goes for a run in the evening. |
| Future Time | I'll be back in ten minutes. |
Common Errors and How to Fix Them
| ✗ Incorrect | ✓ Correct | Why |
|---|---|---|
| I'll see you in Friday. | I'll see you on Friday. | Use on for days of the week. |
| The party is at the evening. | The party is in the evening. | Use in for the morning, the afternoon, and the evening. Use at for night. |
| He was born on 1990. | He was born in 1990. | Use in for years. |
| We don't have school in Monday. | We don't have school on Monday. | Use on for days of the week. |
| I'll be there on 5 minutes. | I'll be there in 5 minutes. | Use in to talk about a period of time in the future. |
Summary
Think of a pyramid. At is the small, specific point at the top. On is in the middle for days and dates. In is the large, general base at the bottom.
| Preposition | General Idea | Examples |
|---|---|---|
| AT | Precise, specific time | at 8 PM, at noon, at the moment |
| ON | Days and dates | on Sunday, on March 5th, on my birthday |
| IN | Longer periods | in April, in 2024, in the summer |
💡 The key takeaway: Remember the exceptions! We say in the morning/afternoon/evening, but at night. We use at for holiday periods like at Christmas, but on for the specific day, like on Christmas Day.