Prepositions of time!

IN

Use 'in' months and years and periods of time:

• in January
• in 1978
• in the twenties

Use 'in' a period of time in the future:

• in a few weeks
• in a couple of days

ON

Use 'on' with days of the week:

• on Monday
• on Fridays

Use 'on' with specific calendar days:

• on Christmas day
• on October 22nd