The rule, as people use it

Think of time as three sizes. The smallest is a point on the clock, and that takes "at": at six, at noon, at midnight, at lunchtime. The middle size is a day or a date, and that takes "on": on Friday, on the third, on my birthday. The biggest is anything longer than a day, and that takes "in": in March, in 2019, in the summer, in the morning.

The one that trips people up is the last group. Parts of the day are "in", because they are long stretches: in the morning, in the afternoon, in the evening. Except night. Night is "at": at night. English does not explain itself here, so say "at night" until it sounds normal.

Examples

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Fill the gap

Type the missing words, then check. The full sentence plays when you get it.

  1. 1

    The train leaves (7:40).

  2. 2

    My sister was born (May).

  3. 3

    Are you free (Tuesday)?

  4. 4

    I usually study (the evening).

  5. 5

    The office closes (noon) on Fridays.

  6. 6

    We first met (2016).

  7. 7

    She works (night), so she sleeps during the day.

  8. 8

    Call me back (the afternoon), any time after two.

Practice · 3 min

Write your own week using all three. Fill each line with something true, then say the whole list out loud twice.

  • I wake up at ___ .
  • I have my first coffee in the ___ .
  • My favorite day is ___ . On that day I ___ .
  • The month I like most is ___ , because in ___ it is ___ .
  • I go to bed at ___ , and I sleep badly at night when ___ .

Say it today

Use it once in a real conversation before tomorrow. Out loud counts, even to yourself.