The most common prepositions of time are: in, on, at, around, between, by, for, from, up until/'til/until and since.
'In' is used to express a period of time in which something has or will happen.
Use ‘in’ with months of the year: ‘IN January’, ‘IN December’, etc.
When talking about years,
Use ‘in’ with the seasons; such as Winter or Spring: ‘It is cold IN winter.’ ‘I hope to go to Paris IN the summer.’
We always say ‘IN the morning’, ‘IN the evening’ and ‘IN the afternoon’.
‘I always drink coffee IN the morning.’
‘I like to read IN the evening.’
‘On’ is used for specific days and dates and usually deals with small blocks of time.
We use 'on' with days of the week: ‘ON Monday, I will go to the bank.’ 'Will I see you ON Saturday?'
In American English, you can say
When we refer to
‘She is leaving the company AT the end of the year.’
'At' is also used to talk about meal times:
'I'll see you AT dinner tomorrow.'
'I got a letter AT breakfast this morning.'
We always say AT night, which is unusual because we say IN the morning and IN the afternoon.
'I love driving at night'.
When we use 'around' and we are talking about the time, it usually means 'approximately'. Take the sentence, ‘I'll meet you at AROUND 10 pm.’ This means that I might be early or late but it will be close to the time of 10 pm.
'Around' is useful for talking about Projects or if you don’t want to commit to a specific time; e.g. ‘I hope to finish the report AROUND the end of next week.’
'Between' means the time between two specific named times:
'BETWEEN now and tomorrow I need to finish my essay.'
'By' and 'for' are both used to indicate a time limit for something to happen:
'I need to hand this essay in BY Wednesday.'
'I need this report FOR Friday.'
'From' is used to describe the beginning of an event:
'FROM now until tomorrow.'
'I lived in Dublin FROM 2012 until 2018.'
'Can you work FROM 7-10 pm tomorrow?'
'Up until' and 'until' are used to describe the time when something is expected to stop. We often replace 'up until' or 'until' by saying ‘til in spoken English:
‘I'll keep studying UP UNTIL midnight - then I have to sleep.’
‘I can’t go to the party. I have to work 'TIL midnight tonight.’
‘Since’ is used to talk about a time when something began or was initiated:
'I have been dancing SINCE I was a child.'
'The brewery has been making beer SINCE 1930.'