in

on

at

in the morning/the evening/the afternoon

months (in May)

seasons (in spring)

years (in 2020)

 

days of the week (on Friday)

dates (on the 15th of May)

particular days (on my birthday/ on that day)

time (at 3 o’clock)

at midday/midnight

word time (at that time, at lunchtime)

at night

at the weekend

at Christmas/ Easter