Prepositions of Time: In, On, At

Quick Answer: Use at for exact times and holiday periods ("at 7 p.m., at Christmas"), on for days and dates ("on Friday, on June 5th"), and in for months, years, seasons and parts of the day ("in March, in 2024, in the morning"). Use no preposition before next, last, this, every, today, tomorrow and yesterday: "See you next week."

Key takeaways

• At = a point in time: at 6:30, at noon, at night, at the weekend (British English).
• On = a day or date: on Monday, on April 1st, on my birthday, on the weekend (American English).
• In = a longer period: in May, in 2010, in winter, in the 1990s, in the morning.
• A named day controls the preposition: in the morning, but on Monday morning.
• No preposition before next, last, this or every: next week, last Monday, every morning.
• On time means punctual; in time means early enough.

What Is the Rule for In, On and At?

Think of a pyramid, from the most specific point at the top to the widest period at the bottom.

Preposition	Size of time	Examples
at	a point, very specific	at 6:30, at noon, at midnight
on	a day or date	on Monday, on April 1st, on my birthday
in	a longer period	in May, in 1999, in the summer, in the 21st century

When Do You Use At?

• at 8 o'clock, at 7:45
• at noon, at midnight
• at sunrise, at sunset
• at lunchtime, at dinner time
• at the moment, at present
• at the same time
• at the beginning, at the end (of something)

Holidays as a period: at Christmas, at Easter, at New Year. (But "on Christmas Day" because it is one day.)

Weekend: "at the weekend" is British English; "on the weekend" is American English.

Night: at night. "I can't sleep at night."

To practice clock times, see how to tell the time in English.

When Do You Use On?

• on Monday, on Tuesdays (meaning every Tuesday)
• on March 15th, on 15 March (British style)
• on my birthday, on our anniversary
• on New Year's Day, on Christmas Eve
• on Friday morning, on Sunday evening
• on weekdays
• on time (punctual)

Notice: "in the morning" but "on Monday morning." When a day is added, the day controls the preposition.

When Do You Use In?

• Months: in January, in October
• Years: in 2010, in 1985
• Seasons: in spring, in the summer
• Decades and centuries: in the 1990s, in the 19th century
• Parts of the day: in the morning, in the afternoon, in the evening
• Periods of time in the future: in ten minutes, in two weeks (meaning after that time)

"I'll be back in ten minutes" means ten minutes from now. "I did it in ten minutes" means it took ten minutes.

For month and season names, see days, months and seasons in English.

When Do You Use No Preposition?

Do not use in, on or at before these words:

Word	Example
next	I'll see you next Friday.
last	We met last year.
this	I'm busy this weekend.
every	She runs every morning.
today, tomorrow, yesterday	Call me tomorrow.
tonight	Are you free tonight?

• Wrong: in next week, on last Monday, at this evening
• Right: next week, last Monday, this evening

In Time vs On Time

Phrase	Meaning	Example
on time	exactly at the planned time	The train left on time.
in time	early enough, before it is too late	We arrived in time to see the start.

Other Time Prepositions

Preposition	Use	Example
for	a length of time	I waited for two hours.
since	from a starting point to now	I have lived here since 2020.
during	within a period	He slept during the film.
from ... to, until	start and end	The shop is open from 9 to 5.
until, till	up to a time	Wait until Friday.
by	not later than	Please finish it by Monday.
before, after	earlier, later	Wash your hands before lunch.
ago	back from now (after the time)	I moved here two years ago.

For and since are especially important with the present perfect tense.

By vs until: "Finish it by Friday" means any time up to Friday, and then it is done. "Stay until Friday" means continue the action up to Friday.

What Are the Most Common Mistakes?

Mistake	Wrong	Right
In with days	in Monday	on Monday
On with months	on July	in July
In the night for habits	I work in the night.	I work at night.
Preposition before next or last	at next week	next week
At with years	at 2019	in 2019
Since with a length of time	since two years	for two years

Turkish-speaker note: Turkish uses the same -de or -da ending for "saat 5'te," "Temmuz'da" and "2019'da," so learners must choose at, on or in by the size of the time, not by the Turkish ending.

Practice Quiz

Fill in at, on, in or nothing (no preposition).

1. My birthday is ___ August.
2. The meeting starts ___ 9:30.
3. We go swimming ___ Saturdays.
4. I was born ___ 2001.
5. What are you doing ___ tomorrow?
6. She studies best ___ night.
7. They got married ___ June 12th.
8. The flowers bloom ___ spring.
9. I'll call you ___ next week.

Answers: 1. in 2. at 3. on 4. in 5. nothing 6. at 7. on 8. in 9. nothing

Want practice that sticks? Start the free LearnLingo course and use time prepositions in short daily-life dialogs with Sage the Turtle.

People Also Ask

What is the rule for in, on and at with time?

Use at for exact times, such as at 5 o'clock. Use on for days and dates, such as on Monday or on May 3rd. Use in for longer periods, such as in July, in 2025 or in the summer.

Is it in the night or at night?

The normal phrase is at night. But we say in the morning, in the afternoon and in the evening.

Do we say on the weekend or at the weekend?

Both are correct. On the weekend is American English and at the weekend is British English.

When do we use no preposition?

Do not use in, on or at before next, last, this, every, today, tomorrow and yesterday. Say next week, not in next week.

Related Reading

• Prepositions of Place in English
• How to Tell the Time in English
• Days, Months and Seasons in English
• 25 Common English Mistakes and How to Fix Them