The year has 12 months, from January to December. Seven have 31 days, four have 30, and February has 28 — or 29 in a [leap year](/leap-years).
The 12 months in order
| # | Month | Days | Name comes from |
|---|---|---|---|
| 1 | January | 31 | Janus, Roman god of beginnings |
| 2 | February | 28 / 29 | Februa, a purification festival |
| 3 | March | 31 | Mars, god of war |
| 4 | April | 30 | Latin aperire, to open |
| 5 | May | 31 | Maia, goddess of growth |
| 6 | June | 30 | Juno, goddess of marriage |
| 7 | July | 31 | Julius Caesar |
| 8 | August | 31 | Augustus Caesar |
| 9 | September | 30 | Latin septem, seven |
| 10 | October | 31 | Latin octo, eight |
| 11 | November | 30 | Latin novem, nine |
| 12 | December | 31 | Latin decem, ten |
September to December are named after 7–10 because the old Roman calendar began in March.
How to remember which months have 31 days
Make a fist: each knuckle is a 31-day month, each dip between knuckles is a shorter month. Or the rhyme — "Thirty days has September, April, June and November."
See any month
Open the live calendar for any country, or browse a single month such as June or December with public holidays and week numbers. For a full year at a glance, see the 2026 calendar.
FAQ
Which months have 31 days? January, March, May, July, August, October and December — seven in total.
Why does February have only 28 days? The Roman calendar left February short; it gains a 29th day in a leap year every four years.