Lesson

At 8 o'clock, on Monday, in April

Time prepositions

≈ 15 min 8 block(s)

Text

When to use at / on / in for time

This lesson explains how to use the prepositions of time: at, on and in. Each preposition is used for different levels of time precision — specific clock times, days/dates, or longer periods such as months and years.

  • at → specific times (at 8 o'clock, at noon, at 3:15 PM)
  • on → days and dates (on Monday, on July 5th)
  • in → months, years, seasons and longer periods (in April, in 2024, in the morning)

Think: at = exact time, on = day/date, in = month/year/period

Table

Prepositions of Time: at / on / in

Preposition Use Example
at Specific times, exact moments The meeting starts at 8 o'clock.
on Days of the week, specific dates The meeting is on Monday.
in Months, years, seasons, longer periods, parts of the day The project begins in April. / We work in the morning.

Tip

Key rule: Match preposition to time precision

Choose the preposition based on how specific the time expression is.

  • Use 'at' for exact clock times and moments: at 8 o'clock, at noon, at midnight.
  • Use 'on' for days and specific dates: on Monday, on July 12th, on my birthday.
  • Use 'in' for months, years, seasons and parts of the day: in April, in 2025, in the morning.

Order tip: with day + time, say 'on Monday at 8 o'clock' (day before time).

Example

Examples in context

The conference call is at 8 o'clock on Monday.

Please submit the report on Monday before 5 PM.

Our new contract starts in April.

We usually review schedules in the morning, but the meeting is at 8 AM.

Tip

Common mistakes to avoid

Learners often confuse these prepositions or omit them. Watch for these universal errors:

  • Using 'in' with a clock time: 'in 8 o'clock' (incorrect) — use 'at 8 o'clock'.
  • Using 'at' with months or years: 'at April' (incorrect) — use 'in April'.
  • Using 'on' with months: 'on April' (incorrect) — use 'in April'.
  • Incorrect order: prefer 'on Monday at 8 o'clock' rather than 'at 8 o'clock on Monday' in formal schedules (both are understood, but the day-before-time order is standard).
  • Omitting the preposition before a time expression: 'Meeting 8 o'clock' (incorrect) — include 'at/on/in' as required.

Check the level of specificity: exact time → at, day/date → on, month/year/period → in.

Quiz

Choose the correct sentence:

Hint: Match each preposition to the type of time expression (time vs day).

Quiz

Complete: The interview is _____ April.

Hint: Think about which preposition we use with months.

Quiz

Choose the correct sentence:

Hint: Focus on which preposition fits a clock time and which fits a day.

Key Points

GrammarPoint

at

preposition CEFR A2 //æt//

Used for specific times and exact moments.

The meeting begins at 8 o'clock.

GrammarPoint

on

preposition CEFR A2 //ɒn//

Used for days of the week and specific dates.

The workshop is on Monday.

GrammarPoint

in

preposition CEFR A2 //ɪn//

Used for months, years, seasons and parts of the day.

The new policy will start in April.

Vocabulary

o'clock

adverb/noun (time expression) CEFR A2 //əˈklɒk//

Used after a number to indicate the exact hour on a 12-hour clock.

The call is scheduled at 9 o'clock.

Vocabulary

appointment

noun CEFR B1 //əˈpɔɪntmənt//

A scheduled meeting or commitment at a specific time.

I have an appointment at 8 o'clock on Monday.

Vocabulary

schedule

noun/verb CEFR B1 //ˈskedʒuːl/ or /ˈʃedjuːl//

A plan of events showing times and dates; to arrange an event at a particular time.

Please schedule the meeting for 8 AM on Monday.