Preposition Of Time

Prepositions of Time: at, in, on
We use:
* at for a PRECISE TIME
* in for MONTHS, YEARS, CENTURIES and LONG PERIODS
* on for DAYS and DATES
at | in | on |
PRECISE TIME | MONTHS,YEARS, CENTURIES and LONG PERIODS | DAYS and DATES |
at 3 o'clock | in May | on Sunday |
at 10.30am | in summer | on Tuesdays |
at noon | in the summer | on 6 March |
at dinnertime | in 1990 |on 25 Dec. 2010 |
at bedtime | in the 1990s | on Christmas Day |
at sunrise | in the next century | on Independence Day |
at sunset | in the Ice Age | on my birthday |
at the moment | in thepast/future | on New Year's Eve |

Look at these examples:
* I have a meeting at 9am.
* The shop closes at midnight.
* Jane went home at lunchtime.
* In England, it often snowsin December.
* Do you think we will go to Jupiter in the future?
* There should be a lot of progress in the next century.
* Do you work on Mondays?
* Her birthday is on 20November.
* Where will you be on New Year's Day?
Notice the use of the preposition of time at in the following standard expressions:
Expression | Example |
at night | The stars shine at night. |at the weekend | I don't usually work at the weekend. |
at Christmas/Easter | I stay with my family at Christmas. |
at the same time | We finished the test at the same time. |
at present |He's not home at present. Try later. |
Notice the use of the prepositions of time in and on in these common expressions:
in | on |
in the morning | on Tuesday morning |
in the mornings | onSaturday mornings |
in the afternoon(s) | on Sunday afternoons |
in the evening(s) | on Monday evening |
When we say last, next, every, this we do not also use at, in, on.
* I went to London lastJune. (not in last June)
* He's coming back next Tuesday. (not on next Tuesday)
* I go home every Easter. (not at every Easter)
* We'll call you this evening. (not in this evening)