Uses of 'in, on, at' as prepositions of time.
A preposition of time is a preposition used to indicate when a particular action takes place. "In," "on," and "at" are commonly used as prepositions of time, and each has specific uses.
In
The preposition ‘in’ is used to refer to longer periods of time, such as a month, year, decade, etc.
Months: in January, in May
Seasons: in summer, in the winter
Years: in 2025, in 1990
Decades: in the 70s, in the 2000s
Centuries: in the 18th century, in the sixteenth century
Periods of history: in the Middle Ages, in the modern era
Periods of time: in a day, in two weeks, in a while, in the last few days
Expressions: in the past, in the future
Parts of the day: in the morning, in the afternoon, in the evening
Examples
I was born in 1995.
I'll travel to Asia in July.
The flowers bloom in spring.
He likes to study in the evening.
I will finish the project in a week.
In the past, people traveled by horse.
The internet became widely used in the 1990s.
In the modern era, global travel has become more accessible.
On
The preposition ‘on’ is used to refer to specific days, dates, and holidays.
Days: on Monday, on Fridays, on weekdays
Dates: on July 4th, on the second of May, on 5 June 1998
Specific days: on my birthday, on Christmas Day
Special occasions: on my graduation, on their anniversary
Day + part of day: on Monday morning, on Saturday night
Examples
The meeting is on Monday.
I like to rest in on Sundays.
The party is on Saturday night.
I received many gifts on my graduation.
We are going to the concert on May 5th.
At
The preposition ‘at’ is used to refer to precise times and specific points in time.
Clock times: at 3:00 PM, at 4 o'clock
Specific times: at night, at noon, at midnight, at sunset, at sunrise, at down
Expressions: at the moment, at this time, at any time
Holidays: at Christmas, at Easter
Mealtimes: at lunchtime, at dinnertime
Examples
I will see you at 3 o'clock.
The meeting starts at 9 AM.
The party is at midnight.
I don't like to drive at night.
We exchange gifts at Christmas.
Usage Notes
'At night' or 'in the night'?
'At night' refers to the general time period when it is dark. It is used to describe things that happen regularly during the nighttime period.
I like to read at night.
She works at night in a hospital.
'In the night' is used when talking about a specific event happened during a particular night.
The power went out in the night.
I heard a strange noise in the night.