How many days are in the months?

A year is divided into 12 months in the modern-day Gregorian calendar. The months are either 28, 29, 30, or 31 days long.

Índice Show

The 12 Months
Tracking the Moon's Orbit
How Many Have 28, 29, 30, or 31 Days?
From 10 to 12 Months
Old Names of Months
How to Remember
See The Days in Each Month
What months have 30 days?
How many days are in each month 2022?
What months have 31 days in it?
How many days in 2022 so far?

The Gregorian calendar is made up of 12 months, each between 28 and 31 days long.

Create Your Calendar

Each month has either 28, 30, or 31 days during a common year, which has 365 days. During leap years, which occur nearly every 4 years, we add an extra (intercalary) day, Leap Day, on 29 February, making leap years 366 days long.

This is to keep our current calendar aligned with the solar year and astronomical seasons marked by equinoxes and solstices.

The 12 Months

The Gregorian calendar consists of the following 12 months:

January - 31 days
February - 28 days in a common year and 29 days in leap years
March - 31 days
April - 30 days
May - 31 days
June - 30 days
July - 31 days
August - 31 days
September - 30 days
October - 31 days
November - 30 days
December - 31 days

Tracking the Moon's Orbit

The months originated as a way to mark time and break up the year into shorter periods based on the Moon’s orbit around Earth. The word month is even derived from the word Moon.

As far as we know, months were first used in Mesopotamia sometime between the years 500 BCE and 400 BCE to measure the natural period related to the lunar month, or synodic month, which is the time it takes for the Moon to go through all the Moon phases.

Moon phases in your city

How Many Have 28, 29, 30, or 31 Days?

The Gregorian calendar has 4 months that are 30 days long and 7 months that are 31 days long. February is the only month that is 28 days long in common years and 29 days long in leap years.

From 10 to 12 Months

Our current Gregorian calendar and its predecessor, the Julian calendar, both have 12 months. However, the month names we use today are derived from the Roman calendar, which initially had only 10 months, with the calendar year starting in March (Martius).

Calendar with holidays

The Romans named some of the months after their position in the calendar year: September means the 7th month, October the 8th, November the 9th, and December the 10th month. However, when January and February were eventually added and the beginning of the calendar year was moved to January, the position of these months no longer corresponded with the original meaning of their names. Today, we still call the 9th month of the year September, the 7th month.

The Islamic calendar, the Hebrew calendar, and the Hindu calendar also use months to divide up the year. Although the Gregorian calendar is the most commonly used calendar today, other calendars are still used in many parts of the world to calculate certain holidays and annual feasts.

Old Names of Months

Months in the ancient Roman calendar include:

Mercedonius - an occasional month after February that would be used to realign the Roman calendar. Today we use Leap Day for this alignment.
Quintilis - renamed July in honor of Julius Caesar in 44 BCE.
Sextilis - renamed August in honor of Roman Emperor Augustus in 8 BCE.

Topics: January, February, March, April, May, June, July, August, September, October, November, December, Months

There are twelve months in a year:

Here are the twelve months in detail:

Month Number	Month	In 3 letters	Days in Month
1	January	Jan	31
2	February	Feb	28 (29 in leap years)
3	March	Mar	31
4	April	Apr	30
5	May	May	31
6	June	Jun	30
7	July	Jul	31
8	August	Aug	31
9	September	Sep	30
10	October	Oct	31
11	November	Nov	30
12	December	Dec	31

February

The strangest month of all is February.

February has only 28 days, but on Leap Years February has 29 days!

How to Remember

You can remember how many days in each month using this rhyme:

30 days has September,
April, June and November.
All the rest have 31
Except February alone,
Which has 28 days clear
And 29 in each leap year.

Or you can use the "knuckle method":

A knuckle is "31 days", and in between each knuckle it isn't.
And where you hands meet, the two knuckles are "July, August", which both have 31 days.
(Note: the last knuckle isn't used)

Example: October is on a knuckles, so it has 31 days

But November is not on a knuckle (and in this case has 30 days)

See The Days in Each Month

See the days in each month (use the arrows to change the month):

images/calendar.js

The Moon

The months were originally based on the movement of the moon (the words moon and month are related), but this did not work out perfectly to one year.

So they changed how many days in some months to make them all add up to one year.

Fun Facts!

Ancient Romans had 10 Months:

Martius for the god Mars
Aprilis (aperio is Latin for "open", and flowers blossom in this month)
Maius for the goddess Maia
Iunius for the goddess Juno
Quintilis from Latin quinque meaning five
Sextilis for six
Septembris for seven
Octobris for eight
Novembris for nine
Decembris for ten (remember "Decimal" means based on 10)

Then around 710 BC Numa Pompilius, the second King of Rome, added January (for the god Janus) and February (from Latin februum meaning purification).

Unfortunately this wrecked the nice numbering system of the later months.

Many years later (44 BC) Quintilis was renamed Iulius (July) in honour of Julius Caesar, and in 8 BC Sextilis was renamed Augustus (August) in honour of Augustus.

1021, 1022, 1023, 1024, 3671, 3672, 3673, 3674, 3675, 3676