At, In, On Prepositions of Time: Simple Guide for Beginners

Beginner

What are prepositions of time?

We use at, on and in to say when something happens.

An easy way to remember them: at is for a point in time, on is for a day, and in is for a longer period.

prepositions of time

PrepositionUseExamples
atexact times
ondays and dates
inmonths, seasons, years, parts of the day

Many learners use on with months (it should be in) or put a preposition before next and last, where we do not need one. We will look at these mistakes at the end.

At

We use at with clock times, mealtimes and some special phrases.

UseExamples
Clock times
Mealtimes and breaks
Night
The weekend
Holidays (several days)

Examples:

  • I get up at 6.30 and go for a run.
  • She does not like to leave the office at lunchtime.
  • The weather is very cold here at Christmas.

At the weekend is British English. In American English, people say on the weekend or on weekends.

At night or in the night? We say at night when we mean the whole night. We say in the night for one moment during the night.

Examples:

  • She is a nurse. She works at night.
  • The baby often wakes up in the night.

On

We use on with days and dates.

UseExamples
Days
Day + part of the day
Dates

Examples:

  • On Fridays, I have a long lunch.
  • It is his birthday on 19 October.
  • We have a lesson on Tuesday morning.

With -s (on Mondays, on Fridays) we mean every Monday, every Friday.

In

We use in with longer periods of time: parts of the day, months, seasons and years.

UseExamples
Parts of the day
Months
Seasons
Years
Decades and centuries

Examples:

  • I usually relax in the evening.
  • In summer it is too hot to do anything.
  • I am always very busy in December.
  • My grandmother was born in 1950.

But remember: in the morning / afternoon / evening, and at night.

Common mistakes

Days → on
Wrong: in Monday
Correct: on Monday
Months → in
Wrong: on July
Correct: in July
Parts of the day → in
Wrong: at the morning
Correct: in the morning
At night
Wrong: in night
Correct: at night
Clock times → at
Wrong: in 5 o'clock
Correct: at 5 o'clock
No preposition
Wrong: on next week
Correct: next week
No preposition
Wrong: in this summer
Correct: this summer
Days → on
Wrong: at Sunday
Correct: on Sunday

No preposition

We do not use at, on or in before these words.

UseExamples
this / next / last
every
today, tomorrow, yesterday

Examples:

  • I am going to the dentist next week. (NOT: on next week)
  • We went to a concert last night.
  • I go for a walk every day.
  • See you tomorrow

Prepositions of time: IN / ON / AT

GRAMMAR REFERENCE

At, In, On: Time

at = a point · on = a day · in = a longer period

✓ AT
exact time
at 7 o'clock
✓ ON
day / date
on Monday
✓ IN
longer period
in July
AT
CLOCK TIME at 6.30
NOON / MIDNIGHT at midnight
MEALTIMES at lunchtime
THE WHOLE NIGHT at night
THE WEEKEND (UK) at the weekend
HOLIDAYS at Christmas
ON
DAYS on Monday
SPECIAL DAYS on my birthday
DAY + PART OF DAY on Tuesday morning
DATES on 5 May
EVERY MONDAY on Mondays
NEW YEAR on New Year's Day
IN
PARTS OF THE DAY in the morning
MONTHS in December
SEASONS in summer
YEARS in 2026
DECADES in the 80s
CENTURIES in the 21st century
NO PREPOSITION
THIS this morning
NEXT next week
LAST last night
EVERY every day
TODAY today
TOMORROW / YESTERDAY tomorrow
AT NIGHT OR IN THE NIGHT?
AT NIGHT
the whole night She works at night.
IN THE NIGHT
one moment The baby woke up in the night.
REMEMBER
Day → on, month → in — on Monday, in July. (not in Monday, on July)
Morning → in, night → at — in the morning, at night. (not at the morning, in night)
No preposition before this, next, last, every — next week. (not on next week)
The weekend — at the weekend (UK) / on the weekend (US)

Practice exercises

At: times and holidays 0 / 7
On and in 0 / 11
At, on, in or nothing 0 / 11
See all