I have found the following usage of "on", "at" and "in" on the internet. Is there any other exception and/or rule for that?

Prepositions of Time

Use in for

  • Months: in April / in September / in that month
  • Seasons: in (the) summer / in (the) winter
  • Years: in 1332 / in 1984 / in that year / in the next year
  • Long Period(s) of Time: in former century / in 90's / in the Ice Age / in the past / in the future

Exceptions: in the morning / in the evening

Use at for

  • Time: at 8 o'clock / at 9:30 / at bedtime / at sunset / at dinnertime / at 5:33:10 AM

Exceptions: at Christmas (= during the Christmas holidays but not necessarily on December 25th) / at Easter / at noon / at night / at the weekend / at the present time / at the moment

Use on for

  • Days: on Monday / on Friday / on Christmas Day (= on December 25th) / on Easter Sunday / on Independence Day
  • Dates: on February 18th / on her birthday / on 21 March 2015 / on


  • We have in the morning and on Monday but we say on Monday morning, not in Monday morning, and so on.
  • When we say last, next, every, this we do not also use at, in, on: She runs next Tuesday. (not on next Tuesday) / He leaves us every Easter. (not at every Easter) / I See you this evening. (not in this evening)
  • Look at these examples for the combination of times in a sentence: We will meet next week at six o’clock on Monday. / I heard a funny noise at about eleven o’clock last night. / It happened last week at seven o’clock on Monday night.

Look at this answer as well which says:

This all hints at a coherent metaphor: hours and other short periods of time are places; days are surfaces; months and longer time periods are containers.


1 Answer 1


The chart could be greatly improved by expanding the category and examples of when we use at. While at is used for clock times, it is also used for other specific times, and thus the many uses are no longer "exceptions" but actual regular uses:

at midnight
at breakfast time
at lunch time
at dinner time
at sunrise
at sunset
at the moment
at (the) present, at the present moment/time
at the right time
at the same time
at dawn
at dusk
at noon
at night
at nighttime

Indeed, we could label at as referring to specific times, and in to refer to relatively nonspecific time periods (akin to During a month, a season, a year, a decade, a century, a nonspecific period of time); while on refers to specific days and dates.

So in would also include:

in the past/future
in those days
in the good old days
in my youth
in my heyday
in my prime
in my old age
in my high school days
in my college years

in the morning, in the mornings
in the afternoon(s)
in the daytime
in the evening(s)
in the night
in the middle of the night

are no longer "exceptions to the rule," but in accord with "nonspecific time periods" (as compared to at night and on Friday nights).

  • 1
    Could we change "in to refer to relatively nonspecific times" to "in to refer to relatively nonspecific time periods"?
    – Ron Jensen
    Commented Dec 3, 2015 at 20:54

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