|At, On, In:
These prepositions are used to show the time and date of events, activities and situations:
e.g. at three o'clock. in June. on Monday.
at + particular time: dawn, midday, noon, night, midnight, nine o'clock etc.. e.g. at dawn.
at + the + a particular time in a week/month/year: start/end of the week/month/year, weekend. e.g. at the start of July.
at + calendar festival season: Christmas, New Year, Easter etc.. e.g. at Easter.
at + meal: breakfast, lunch, mid-morning, tea, dinner, supper etc.. e.g. at breakfast.
on + day of the week: Monday, Tuesday, Wednesday etc. e.g. on Thursday.
on + particular part of a day: Friday morning, Saturday afternoon. e.g. on Sunday evening.
on + particular date: 25 July 2001, 4 January. e.g. on 19 March.
N.B. On the nineteenth of March is how this date is read aloud or said in conversation.
on + calendar festival day: Christmas Day, Palm Sunday. e.g. on Easter Sunday.
in + the + a part of a day: the morning, the afternoon, evening. e.g. in the afternoon.
in + month: January, February, March, April, May etc.. e.g. in June.
in + season of the year: Spring, Summer, Autumn. e.g. in Winter.
in + specific year: 1988, 1989, 1990 etc.. e.g. in 1999.
in + the + a specific century: nineteenth century. e. g. in the twentieth century.
in + historical period of time: the Dark Ages, Pre-historic Times. e.g. in the Middle Ages.
N.B. No preposition is used if the day/year has each, every, last, next, this before it:
e.g. I go to England every Christmas ( not at every Christmas )
I'll see you next Monday afternoon. ( not on Monday afternoon )
Martin left home last evening. ( not in the evening )