Prepositions of Time in English: List, Rules, and Examples

Prepositions of time show when something happens, how long it lasts, or how one event relates to another in time. Common examples include at, on, in, before, after, during, for, since, by, and until.

Consider these sentences:

The research team arrived at sunrise.

They remained at the site for three days.

Their findings were presented after the expedition.

The examples describe three different aspects of the expedition: when the team arrived, how long it stayed, and when its findings were presented.

List of Common Prepositions of Time with Examples

Some prepositions identify a particular moment. Others describe a period, a starting point, or a deadline.

Some entries, such as between … and and as of, are multiword expressions rather than single prepositions.

At, On, and In: Specific Times, Dates, and Periods

At, on, and in are commonly used with clock times, calendar dates, and longer periods.

At for Specific Times

At identifies a particular time or moment.

The overnight train departs at 11:45 p.m.

We reached the harbor at dawn.

Other familiar expressions include at noon, at midnight, at sunrise, and at lunchtime.

On for Days and Dates

On is normally used with days of the week, calendar dates, and particular days.

The museum will reopen on Thursday.

The agreement was signed on 18 February.

It also appears when a part of the day is connected to a particular day.

The rescue operation began on a cold January morning.

In for Longer Periods

In is common with months, years, seasons, centuries, and general parts of the day.

The coastal railway was completed in the nineteenth century.

Wildflowers cover the hillside in spring.

We usually review the applications in the afternoon.

Not every time expression follows these basic patterns.

At night is the usual expression when referring to nighttime generally, while in the night can describe something happening during a particular night.

British English commonly uses at the weekend, whereas American English more often uses on the weekend.

Expressions such as at night, on Monday morning, and in the morning are explored more fully in At vs On vs In.

Before, After, From, and To: Order and Time Ranges

Before and after establish the order of events. From … to and between … and describe time ranges.

Before and After

A hearing may provide the reference point for two very different deadlines.

The documents were submitted two days before the hearing.

The documents were submitted two days after the hearing.

Changing the preposition changes whether the submission happened earlier or later.

You can also use these prepositions without specifying an interval.

We inspected the building before the reopening.

Traffic gradually returned to normal after the celebrations.

From … To and Between … And

From … to identifies the beginning and end of a period.

The photography course runs from September to December.

Between … and identifies a range bounded by two times.

Your replacement parts should arrive between Tuesday and Thursday.

The course has a stated period, while the delivery is expected at some point within a given window. Both constructions can describe other kinds of time ranges, so the distinction depends on the situation rather than a strict grammatical rule.

American English also commonly uses through in date ranges.

The library will be closed Monday through Wednesday.

This includes Wednesday. With from Monday to Wednesday, whether Wednesday is included may depend on the context.

By, Until, Before, and Within: Understanding Time Limits

A change in preposition can turn a scheduled date into a deadline or a restriction.

Imagine that a design team is preparing a proposal for a client.

The distinction between by and before matters when communicating deadlines. By Friday includes Friday as the latest acceptable day, while before Friday excludes it.

Until and Not Until

Until usually describes a situation or activity continuing up to a particular point.

The repair team will remain on site until 6 p.m.

The team stays there up to that time.

In negative sentences, not until can indicate that something does not happen before a stated point.

The examination results will not be available until Monday.

This tells us the results cannot be obtained before Monday. It normally suggests that they will become available on Monday, although the statement alone does not guarantee that outcome.

Till has the same basic meaning as until and is particularly common in informal English.

Within and In

Within describes a time limit measured from a stated or understood starting point.

You should receive a confirmation email within two hours of registering.

The email may arrive earlier, but it should arrive no later than the end of that period.

Compare:

The specialist will arrive in two hours.

The specialist will arrive within two hours.

An arrival in two hours is expected around that time. Within two hours allows an earlier arrival.

However, in can also describe how long an activity takes to complete.

A local conservation group restored the damaged footpath in three days.

Here, three days measures the time taken to finish the work.

For, Since, During, Throughout, and Over: Periods of Time

For and Since

For measures duration.

We stayed in the mountain village for four months.

Since identifies a starting point in the past.

This collection has been open to researchers since 2005.

The collection became available in 2005 and remains available now.

Since can also refer to a period ending at a past reference point.

By the time the building reopened, it had been closed since the previous winter.

The past perfect connects the closure’s starting point to the later reopening.

The distinction between starting points and durations, along with their different tense patterns, is covered in Since vs For: When to Use Each.

During and Throughout

During places something within a named event or period.

Several interruptions occurred during the broadcast.

Throughout emphasizes an entire period.

The emergency alert remained visible throughout the broadcast.

The interruptions happened at particular points, while the alert stayed visible across the whole broadcast.

During can also refer to an activity lasting for an entire period. Throughout simply makes that whole-period meaning more explicit.

Over

Over often describes developments, changes, or activities across a period.

What began as a small fishing village became a busy trading port over the following fifty years.

It also appears in expressions such as over the weekend, over the holidays, and over the past few months.

Unlike since, over does not itself identify a particular starting point.

When No Preposition of Time Is Needed

English does not always require at, on, or in before a time expression.

These prepositions are normally omitted before expressions beginning with this, next, last, every, and each when they directly identify when something happens.

Incorrect: The committee will meet on next Tuesday.

Correct: The committee will meet next Tuesday.

Incorrect: We visited the old theatre in last winter.

Correct: We visited the old theatre last winter.

Incorrect: The inspection takes place on every Friday.

Correct: The inspection takes place every Friday.

The same applies to time adverbs such as yesterday, today, and tomorrow.

The publisher announced the revised release date yesterday.

However, these expressions can follow other prepositions when the meaning requires one.

The office has been closed since last Thursday.

The repairs must be finished before next Monday.

So we say next Tuesday, not on next Tuesday, when simply identifying the day of an event.

Prepositions of Time and Other Time Words

Not every word that expresses time is a preposition. Some words have different grammatical functions depending on how they are used.

During vs While

During is a preposition followed by a noun phrase.

Several safety concerns emerged during the inspection.

While acts as a conjunction when it introduces a clause.

Several safety concerns emerged while the inspectors were examining the structure.

Both describe overlapping events, but their sentence patterns differ.

Incorrect: During the inspectors were examining the structure, they discovered a leak.

Correct: While the inspectors were examining the structure, they discovered a leak.

In traditional grammar, words such as before, after, since, and until are also classified as conjunctions when they introduce clauses.

Ago and Other Time Expressions

Ago is generally classified as an adverb rather than a preposition.

It follows an expression of duration and refers to a point in the past.

The original manuscript disappeared more than seventy years ago.

Other useful expressions include around and about for approximate times, as of for the beginning of a new arrangement, and past and to when telling the time. Their common uses appear in the reference table above.

On Time vs In Time

On time means at the scheduled or expected time.

Despite the severe weather, the train arrived on time.

In time means early enough for something to happen or be done.

The medical supplies reached the remote village in time to prevent further shortages.

Something can arrive in time without arriving exactly on schedule.

A small change in a time preposition can change whether a sentence describes a schedule, a duration, or a deadline. The surrounding context usually makes the intended relationship clear.

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