2025.10.06

Expressions of Date, Day, and Season in English｜How to Use in, on, at with Example Sentences

Izumi

When talking about plans, schedules, or events, expressions such as “at 5 o’clock,” “on Monday,” or “in July” are indispensable. In English, it is necessary to distinguish among the prepositions at, on, and in.

In this lesson, I will explain the rules for using these prepositions in relation to time expressions—dates, days, and seasons—together with example sentences.

Contents

1. Basic Rules of Time Expressions
- 1-1. How to Choose the Preposition: Based on the “Size of Time”
2. Key Points of Each Preposition
3. Summary

1. Basic Rules of Time Expressions

For time expressions, the three prepositions at, on, and in occur frequently. Which one to choose is a crucial point that determines meaning.

1-1. How to Choose the Preposition: Based on the “Size of Time”

The choice of preposition depends on the “size” of the time span in which an event occurs.

Preposition	Target Time	“Size” of Time	Examples
at	Specific times or moments	Small / a point in time	at 6:30, at noon, at night
on	Dates, days of the week, specific days	Medium / one-day unit	on Monday, on July 1st
in	Months, years, seasons, times of day	Large / periods or spans	in April, in 2025, in summer

To summarize:

at: for smaller, specific points in time.
on: for single-day events.
in: for larger spans such as months, years, and seasons.

2. Key Points of Each Preposition

2-1. at: For Specific Times or Moments

At is used for pinpoint times or specific moments.

at 7 o’clock
at noon
at midnight
at the moment

Any expression that refers to a specific point within a day generally takes “at ”. For example:

at lunch
at sunrise

2-2. on: For Days, Dates, and Single-Day Events

On is used for events that occur on a one-day basis.

on Monday
on Christmas Day
on July 4th

Expressions that combine month and date (e.g., on July 1st) also take on, since they refer to one specific day.

Note

There is a difference between British and American English when referring to weekends:

on the weekend (commonly used in British English)
on weekends (used in American English to mean “every weekend”)

2-3. in: For Periods of Time

“In ” is used for months, years, seasons, and times of day.

in April
in 2024
in spring
in the morning / afternoon / evening

The basic form is “in + time span”. It conveys the sense of being “within” a period of time.

Exception: Only “night” uses “at night ”instead of “in the night.”

3. Summary

at is used for specific times or moments (e.g., at 5:00, at midnight).
on is used for days, dates, or single-day events (e.g., on Monday, on July 1st).
in is used for larger periods such as months, years, seasons, and times of day (e.g., in July, in spring, in the morning).
The choice of preposition depends on the “size of time.”
Pay attention to exceptions such as “at night.”

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