When is your birthday? Mine is ON October 12. When do you eat lunch? I usually eat it AT noon. When does the school year begin in your country? In mine it begins IN September.
Do you know which preposition to use before times, days, months and years? Here is a reminder.




Don't forget to use...

in + month or year- In March, In 2003
on + date (with the year or without it) or day of the week- On April 2, On March 3, 1999, On Saturday
at + clock time, midnight, noon- At 3:30 p.m., At 4:01, At noon

Remember also...

in + season- In the summer, In the winter
in + morning, afternoon, evening- In the morning, In the evening
at + night- At night