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Prepositions of Time in English: At, On, In for Talking About Time
At for exact times, on for days and dates, in for longer periods like months and years.
Written by Bryan López, Profesor de inglés · Updated
At, on, and in are also used to talk about time, not just place. At is for exact times (at 3:00), on is for days and dates (on Monday), and in is for longer periods like months, years, and seasons (in July, in 2024).
At, on, in for time
The 'at night' exception
You say "in the morning," "in the afternoon," and "in the evening," but night is the exception: it's "at night," not "in the night."
No preposition before next, last, this, every
You never use in, on, or at before next, last, this, or every: "next week" (not "in next week"), "last month," "this year," "every day."
Common mistakes with prepositions of time
In many languages, one word covers almost all time uses (the equivalent of "in the morning" and "in 2024"), so it's common to use "in" for everything in English, even exact times or days. "In 3:00" or "in Monday" are wrong, they should be "at 3:00" and "on Monday."
During, for, and since: often confused
"For" says how long something lasts: "I studied for two hours." "Since" says when it started and is used with perfect tenses: "I have lived here since 2020." "During" says when something happened inside a period: "I woke up twice during the night." A simple way to remember: for + a length of time, since + a starting point, during + a named period or event.
Practice prepositions of time with real audio
Interactive exercises, real pronunciation, and the full lesson taught in English.
Time prepositions at a glance
By versus until
"By" means no later than a certain moment: "Please send the report by Friday" means Friday is the last day to do it. "Until" means the situation continues up to that moment: "I'll be in the office until Friday" means you stay there each day until Friday. The two are easy to swap by mistake, but the meaning changes: one is a deadline, the other is a duration.
Examples of prepositions of time
- The shop opens at 9 a.m. and closes at 6 p.m.
- We have a meeting on Tuesday afternoon.
- She was born in 1998, in the spring.
- I've known him since we were kids.
- He worked in a bank for ten years.
A common mistake with prepositions of time
Incorrect
I will see you in Monday.
Correct
I will see you on Monday.
Time prepositions in real conversation
A: "When does your class start?" B: "At eight, on weekdays, and it finishes at noon." A: "Are you free on Saturday?" B: "Yes, but only until five. I have to be home by six." A: "No problem. I've been waiting for this weekend since March!"
Frequently asked questions
What's the difference between at, on, and in for time?
At is for exact times (at 3:00), on is for days and dates (on Monday), in is for longer periods like months and years (in July, in 2024).
When do you use at for time?
For exact times and specific moments: at 3:00, at night, at lunch, at the moment.
When do you use on for time?
For days of the week and specific dates: on Monday, on June 5th, on Christmas Day.
When do you use in for time?
For months, years, seasons, and parts of the day (except night): in July, in 2024, in winter, in the morning.
Why do you say "at night" and not "in the night"?
It's a fixed exception: even though the other parts of the day use "in" (in the morning, in the afternoon), night always uses "at night."
Is a preposition used before next, last, this, or every?
No. You never use in, on, or at before these words: "next week," "last year," "this month," "every day."
Do we say in the morning or at the morning?
In the morning, in the afternoon, in the evening. The exception is "at night."
Is it on the weekend or at the weekend?
Both are correct. American English prefers on the weekend and British English prefers at the weekend.
Do we use a preposition with today, tomorrow, and yesterday?
No. You say "I'll call you tomorrow," not "on tomorrow."
What is the difference between in time and on time?
On time means exactly at the planned moment: "The bus arrived on time." In time means early enough: "We arrived in time to catch the train."
How do I remember at, on, and in?
Think of size: at is for a precise point (at 6:00), on is for a day or date (on Friday), and in is for a longer period (in July, in 2024).
Practice prepositions of time with real audio
Interactive exercises, real pronunciation, and the full lesson taught in English.
Keep learning
- Prepositions of Place in English: In, On, At, and MoreIn, on, and at are the three place prepositions that get confused the most in English, each with its own rule.
- Prepositions of Movement in English: To, From, Into, Out OfThey describe movement from one place to another: to, from, into, out of, through, across, and more.
- Adverbs of Frequency in English: Always, Usually, Often, Sometimes, NeverAlways, usually, often, sometimes, rarely, and never say how often something happens, and they have a fixed spot in the sentence.