Practice
Prepositions of time: use at, on, and in accurately
Sign in to saveYour appointment is at 10:15, your class is on Thursday, and your holiday is in August. The three prepositions are short, but they point to different kinds of time.
Choose at, on, or in for a clock time, a day or date, a month, a year, a season, or a part of the day.
Read and practice
Read the examples and try the written questions in this guide. Listening recordings are not available for this lesson yet.
Try the written questions
on Monday morning /ɒn ˈmʌn.deɪ ˈmɔː.nɪŋ/
The short answer
Use at for a precise time, on for a day or date, and in for a longer period. For example, use at 8:00, on Saturday, and in July.
The lesson begins at quarter to nine.
Why it works: Quarter to nine is one precise time on the clock, so it takes at.
6 more examples
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The shop closes at 6:30 on weekdays.
At is used with a precise clock time.
Not this:The shop is quieter
in the evening. What changes: In the evening gives a broad period, not one exact time. -
Our neighbours arrive on Saturday.
Saturday is a named day, so it takes on.
Not this:Our neighbours arrive
in September. What changes: September is a month, so it takes in. -
The museum opens on 14 April.
A calendar date identifies one day, so it takes on.
Not this:The museum opens
in April. What changes: In April does not name the exact day. -
I started my new job in 2025.
A year is a longer period, so it takes in.
Not this:I started my new job
on 3 January 2025. What changes: The full date identifies one particular day. -
We usually eat outside in the summer.
A season is a broad period, so it takes in.
Not this:We usually eat outside
on Sunday afternoon. What changes: Sunday is the named day, so the complete phrase takes on. -
The street is quiet at night.
At night is a common fixed time expression.
Not this:The street is busy
in the morning. What changes: Morning is a broad part of the day, so it usually takes in.
Read the full guide
Look first at the words after the blank. A clock time needs at. A weekday or calendar date needs on. A month, year, season, or broad part of the day needs in. If the phrase starts with next, last, this, every, or each, check whether English uses no preposition at all.
Start with the kind of time expression
The word after the preposition gives you the first clue. A time on a clock is a point. A weekday or date is one day. A month, year, season, or part of the day is a wider period. Sort the phrase before you choose the preposition.
The bus leaves at 7:20.
At 7:20 gives one point on the clock. In July gives a period with many possible days and times.
Which word fits a time on a clock: at, on, or in?
Use at: The bus leaves at 7:20.
Use at for points and fixed phrases
Use at with clock times, noon, and midnight. It also appears in fixed phrases such as at night. These phrases are useful to learn as a group because night does not follow the usual pattern for parts of the day.
The meeting starts at noon.
The baby often wakes up at night.
Use at noon for one point in the day. Use at night because it is the usual phrase in English.
Choose the right word: The train leaves ___ midnight.
Use at because midnight is one point in time.
Use on for days and dates
Use on with weekdays and calendar dates. Use it for a particular day plus a part of the day too. Monday morning is still connected to Monday, so it takes on.
My brother has a driving lesson on Friday.
We are visiting our aunt on Sunday afternoon.
In the afternoon is general. On Sunday afternoon names one afternoon on a particular day.
Choose the right word: Her birthday is ___ 8 November.
Use on because 8 November is a calendar date.
Use in for longer periods
Use in with months, years, seasons, and general parts of the day. These expressions describe a period rather than a single point or a named day.
The school term ends in December.
We go for a walk in the evening.
In December gives a month. On 12 December gives one day inside that month.
Choose the right word: They moved here ___ 2018.
Use in because 2018 is a year.
Learn the common exceptions as phrases
Some frequent time phrases do not use the basic pattern. Say at night, but in the morning, in the afternoon, and in the evening. Do not usually add a preposition before next, last, this, every, or each.
I will call you next week.
She visited us last Saturday.
Next week and last Saturday already contain words that place them in time, so they do not normally need in or on.
Choose the complete phrase: in next week or next week?
Use next week. Do not add in.
Before you go
Remember this
Use at for a point in time, on for a day or date, and in for a larger period. Then check the complete phrase. Remember at night, in the morning, on Monday morning, and no preposition in phrases such as next week or last year.
Practice with the written examples
You can practice with the written questions in the Learn tab. Each answer includes an explanation.
Try the written questionsListening test not available yet
This lesson does not have the recordings needed for a listening test. Use the written questions in the guide to check your understanding.
Try the written questionsQuestions about "Prepositions of time: use at, on, and in accurately"
When do I use at for time?
Use at for a precise time on a clock, such as at 6:30, and for fixed phrases such as at noon, at midnight, and at night. It usually points to one time rather than a whole day or month.
The shop closes at 6:30 on weekdays.
Why do we say on Monday but in July?
Use on with a named day or date, so Monday takes on. Use in with a month, year, season, or broad part of the day, so July takes in. The choice follows the kind of time expression.
The shop is quieter in the evening.
Do I use on with a date?
Yes. Use on with a calendar date because it identifies one day, as in on 14 April. Use in when you mention only the wider month or year, such as in April or in 2025.
Our neighbours arrive on Saturday.
Why do we say at night but in the morning?
At night is a common fixed phrase. Morning, afternoon, and evening usually take in when you mean a general period: in the morning, in the afternoon, and in the evening. Learn these complete phrases.
Our neighbours arrive in September.
Do next week and last Friday need a preposition?
Usually no. Do not normally add at, on, or in before next, last, this, every, or each in time phrases. Say next week, last Friday, this evening, every day, and each year.
The museum opens on 14 April.