Calendar Wiki

The 31.5 Day Month Calendar is a calendar that technically has 31.5 days in a month.

January: 31 (sometimes 32)

February: 32

March: 31

April: 32

May: 31

June: 32

July: 31

August: 32

September: 31

October: 32

November: 31

October: 32

Total: 378 or 379 days

Calendar corrections[]

5 months have 32 days and 5 months have 31 days due to calendar corrections, as to technically say each month is 31.5 days long.

Every 2 years, January gains an extra day, so January has 32 days.

This results that in a leap year January is the only odd numbered month with 32 days.

Another calendar correction is that the reason why we have a 2 year leap cycle is so that in a cycle, half of the years would have a 32-day January. For example, in a 4 year cycle, the 1st year January would have 31 days, 2nd 32 days, 3rd 31 days, and 4th 32 days. This means in 2 years January has 32 days. In a 100-year cycle, 50 years would have 32 days, in a 400-year cycle, 200 years would have 32 days, etc.

Other calendars[]

This is technically the 54-Week Calendar

but the months have 31 or 32 days.