Prepositions of Time

Master at, on, and in to express when things happen in English

Prepositions of Time: At, On, In

These three little words – at, on, and in – are essential for talking about when things happen. While they may seem simple, choosing the right one can be tricky! The key is understanding that they represent different levels of specificity: "at" for precise points in time, "on" for days and dates, and "in" for longer periods.

Think of it like this: "at" points to an exact moment, "on" covers a whole day, and "in" spans weeks, months, or years. Master these rules, and you'll sound much more natural when discussing time in English.

AT - Specific Points in Time

Use "at" for precise moments and clock times:

Clock times: I wake up at 7:00 AM.
The meeting starts at 3:30 PM.
She arrives at midnight.
The store closes at 9 o'clock.
Lunch is at noon.
The movie begins at quarter past eight.

Use "at" for specific moments of the day:

We eat at breakfast.
I'll call you at lunchtime.
The sky is beautiful at sunrise.
It gets cold at night.
Traffic is terrible at rush hour.

Use "at" for holidays (without "day"):

We exchange gifts at Christmas.
Fireworks go off at New Year.
Families gather at Thanksgiving.
Children trick-or-treat at Halloween.

Special expression:

At the weekend (British English)
At the moment (right now)
At the same time

ON - Days and Dates

Use "on" for days of the week:

I have a meeting on Monday.
She goes to yoga on Wednesdays.
The shop is closed on Sundays.
We'll meet on Friday.
They play football on Saturdays.

Use "on" for specific dates:

My birthday is on July 15th.
The deadline is on March 31st.
Independence Day is on the 4th of July.
The exam is on December 10th.
We're leaving on the 20th.

Use "on" for specific days (day + time):

On Monday morning, I have class.
Let's meet on Friday evening.
On Saturday afternoon, we went shopping.
I'll call you on Tuesday night.

Use "on" for holidays with "day":

We celebrate on Christmas Day.
On New Year's Day, everything is closed.
I was born on Thanksgiving Day.
On Independence Day, there are fireworks.

Special expression:

On the weekend (American English)
On my birthday
On that day

IN - Longer Time Periods

Use "in" for months:

School starts in September.
It snows a lot in January.
My wedding is in June.
Halloween is in October.
Spring begins in March.

Use "in" for years and decades:

I was born in 1995.
She graduated in 2020.
The internet became popular in the 1990s.
In 2030, technology will be very different.
World War II ended in 1945.

Use "in" for seasons:

Flowers bloom in spring.
It's hot in summer.
Leaves fall in autumn/fall.
It snows in winter.

Use "in" for parts of the day:

I exercise in the morning.
She studies in the afternoon.
We relax in the evening.
BUT: at night (exception!)

Use "in" for periods of time (how long something takes):

I'll finish in 10 minutes.
She'll arrive in an hour.
The project will be done in two weeks.
I'll be back in a moment.

Common Mistakes

❌ I'll see you in Monday. → ✅ I'll see you on Monday.
❌ The party is on May. → ✅ The party is in May.
❌ The meeting is in 3:00. → ✅ The meeting is at 3:00.
❌ I was born at 1990. → ✅ I was born in 1990.
❌ We'll meet in Saturday. → ✅ We'll meet on Saturday.
❌ She works at the morning. → ✅ She works in the morning.
❌ My birthday is in June 5th. → ✅ My birthday is on June 5th.
❌ I'll call you on 10 minutes. → ✅ I'll call you in 10 minutes.

Practice Tips

🎯 Size matters: Think of at/on/in from smallest to largest. AT = point, ON = day, IN = longer period. This visual helps!
⏰ Clock = AT: If you can see it on a clock face, use "at." At 5:00, at midnight, at noon.
📅 Calendar = ON: If it's a box on a calendar (a specific day or date), use "on." On Monday, on April 15th.
📆 Span = IN: If it spans multiple calendar boxes (months, years, seasons), use "in." In March, in 2024, in summer.
🌙 Night is special: Remember "at night" is the exception – even though "night" is a period, we say "at night," not "in the night."
✍️ Make time sentences: Practice by writing 10 sentences about your schedule using at/on/in correctly. "I wake up AT 7. I have class ON Monday. I was born IN 1995."

Prepositions of Time