How Many Months Of The Year Have 28 Days?

Image source: Wikimedia Commons

You may be wondering how many months of the year only have 28 days in them. The answer is 1, February but that only applies when it’s not a leap year when February has 29 days.

Remembering how many days each month has is quite a pain, but there is always one month you can remember; February is the only month that has only 28 (or 29) days. If we want to get specific (and snarky), all 12 months of the year have at least 28 days. One of the biggest questions is why is February the only month that has 28 (or 29) days, and what is a leap year? To learn all about it check out this guide.

February is always a bad month for TV sports. Football is gone, basketball is plodding along in the annual midseason doldrums, and baseball is not even mentioned. – Hunter S. Thompson

In case you are wondering, here are the number of days each month has:

How Many Days Does Each Month Have?
MonthDay
January31
February28 (or 29 in a leap year)
March31
April30
May31
June30
July31
August31
September30
October31
November30
December31

Why Are There Only 28 Days In February?

Image source: Pexels

As with so many things in our society, the reason February has only 28 days is the fault of the ancient Romans.

Note: A lunar year has 355 days (the lunar cycle is 29 days long)

The Romans came up with the first calendar that society recognized, and it had a glaring difference from the calendar we know today; it only had 10 months instead of 12. In this calendar the year actually started in March and ended in December, meaning that February and January didn’t exist. Here are the months, their translations, and the number of days each month had:

Romulus Calendar
Month (Latin and English)TranslationDays
Mensis Martius (March)Month of Mars31
Mensis Aprilis (April)Month of Aphrodite30
Mensis Maius (May)Month of Maia31
Mensis QuintilisFifth Month31
Mensis SextilisSixth Month30
Mensis SeptemberSeventh Month30
Mensis OctoberEighth Month31
Mensis NovemberNinth Month30
Mensis DecemberTenth Month30
Total Days Of The Year:274

This calendar was made by the very first Roman king Romulus and though it is somewhat unclear why this calendar didn’t actually match up to the lunar calendar, the general belief is that January and February were not included because there were no harvesting crops in those months anyway. Romulus’ successor, Numa Pompilius, revised the calendar and added January and February in, making it line up much closer with the lunar calendar.

When King Pompilius added those two extra months he had to try to avoid having months with an even amount of days. Romans had a pretty serious superstition that even numbers were unlucky, so they typically tried to avoid them. So, in order to actually match up to the lunar year (355 days) one of the 12 months had to have an even number of days. February was chosen to have 28 days and was used as the month the Romans’ would honor their dead. Numa’s new calendar wound up looking like this:

Numa’s Calendar
Martius31 Days
Aprilius29 Days
Maius31 Days
Iunius29 Days
Quintilis31 Days
Sextilis39 Days
September29 Days
October31 Days
November29 Days
December29 Days
Ianuarius29 Days
Februarius28 Days
Total Days:355

After a period of time, it became clear that the calendar was not staying synced up with the seasons since it didn’t actually take into account the amount of time the Earth took to rotate around the sun. So, in 45 BC Julius Caesar hired someone to make a calendar that was considerably more accurate and sun-based. To do this 10 extra days were added into the year, and an extra day was added into February.

The Julian calendar had a total of 365 days over a period of 12 months. This calendar took effect January 1st, 45 BC and stayed in effect until 1582. Here is the Julian calendar:

The Julian Calendar
MonthDays from Roman CalendarDays in Julian Calendar
Ianuarius (January)2931
Februarius (February)2828 (29 on leap years)
Martius (March)3131
Aprilis (April)2930
Maius (May)3131
Iunius (June)2930
Quintilis (July)3131
Sextilis (August)2931
September2930
October3131
November2930
December2931
Total Days:355365

Our society now uses the Gregorian calendar, named after Pope Gregory XIII. This calendar was introduced in 1582 and accounts for leap years every 4 years. According to the Astronomical Applications Department, the rule for leap years is (can also be found here):

Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the year 2000 is. The Gregorian dates for Easter are computed from a set of ecclesiastical rules and tables

The Gregorian calendar basically just shortened down the Julian calendar by 1/4 so that the days lined up better with equinoxes. When this was placed into effect it was so drastic that October 4th, 1582 was followed by October 15, 1582. If we thought we complained about daylight savings time imagine losing multiple days of the year randomly. This calendar was originally adopted by European Catholics first and eventually, the rest of the world followed suit.

Swapping to the Gregorian calendar. Image source: Wikimedia Commons

The Gregorian calendar is:

The Gregorian Calendar
MonthDays
January31
February28 (or 29 in a leap year)
March31
April30
May31
June30
July31
August31
September30
October31
November30
December31
Total:365

Facts About The Gregorian Calendar

  • The primary goal of the Gregorian calendar was to change the date of Easter
    • Needed to fall of the Spring equinox
  • This calendar is “only” 26 seconds off of the solar year
    • By 4909 the Gregorian calendar will be a day ahead of the actual solar year
  • Because of this, we have leap seconds
  • The Gregorian calendar is only 11 minutes different from the Julian calendar
  • Saudi Arabia switched to the Gregorian calendar in 2016
  • The United States of America adopted the Gregorian calendar in 1752 and ended up losing 11 days when swapping to it
  • There is no perfect calendar, and things might change again at some point in the future

Facts About February

  • The name February is Roman and means “purification”
  • February is the only month that can not have a full moon
  • February’s birthstone is amethyst
  • Horoscopes for February:
    • Aquarius (January 20 – February 18)
    • Pisces (February 19 – March 20)
  • Groundhog Day is in February and is a Garman superstition
Written By
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