How to Instantly Know Which Months Have 31 Days

By Lilo Last updated Jan 3, 2025

Ever forgotten how many days are in a specific month? It happens to everyone, but there are timeless tricks to help you instantly figure it out. With just your hands or a memorable rhyme, you can confidently recall the number of days in each month, whether for planning events or simply satisfying curiosity.

The Knuckle Counting Trick

The knuckle method is a clever, hands-on way to remember which months have 31 days. Here’s how it works:

1. Make a Fist

Form a fist with one hand. Your knuckles and the dips (valleys) between them represent the months of the year.

2. Assign the Months

Start with the first knuckle (closest to your thumb) as January.
The valley next to it is February.
Continue alternating knuckles and valleys for the rest of the months:
- Knuckle: March
- Valley: April
- Knuckle: May
- Valley: June
- Knuckle: July

3. Switch Hands or Restart

When you reach July, start again with the first knuckle for August and continue:

Knuckle: August
Valley: September
Knuckle: October
Valley: November
Knuckle: December

4. Decoding the Days

Knuckles: Represent months with 31 days (January, March, May, July, August, October, December).
Valleys: Represent months with 30 days (April, June, September, November), except for February, which has 28 or 29 days.

The “Thirty Days Hath September” Rhyme

Another timeless method is the classic rhyme:

“Thirty days hath September, April, June, and November.
All the rest have thirty-one,
Excepting February alone,
Which has twenty-eight days clear,
And twenty-nine in each leap year.”

This rhyme makes it easy to remember that September, April, June, and November have 30 days, while all others (except February) have 31.

Practical Example

Let’s figure out how many days are in September:

Knuckle Method: Count on your knuckles and valleys until you reach September. Since it’s a valley, it has 30 days.
Rhyme: Recite the rhyme—“Thirty days hath September…”—and confirm that September has 30 days.

Both methods give the same answer, making them equally reliable.

Why These Tricks Are Timeless

These methods are simple, practical, and universally accessible:

No Tools Required: All you need are your hands or the rhyme stored in your memory.
Great for Kids: The interactive knuckle trick or the catchy rhyme turns learning into a fun activity.
Easy to Remember: The visual and verbal cues make these techniques hard to forget.

Fun Calendar Facts

Why February Has Fewer Days: February was shortened in the Roman calendar to align with the lunar year and later adjusted to fit the Gregorian calendar.
Origins of the Calendar: The modern Gregorian calendar was introduced in 1582 to fix errors in the Julian calendar, ensuring better alignment with Earth’s orbit.
Why Some Months Have 31 Days: Ancient Romans adjusted the calendar, adding and rearranging days to honor different deities and align with seasonal changes.

Everyday Uses

These tricks come in handy for:

Travel Planning: Determining trip lengths based on the number of days in a month.
Bill Payments: Avoiding late fees by remembering shorter months like February.
Event Scheduling: Ensuring accurate dates for meetings, holidays, or vacations.

Conclusion

The knuckle trick and the “Thirty Days Hath September” rhyme are tried-and-true methods for remembering the days in each month. Whether you’re teaching a child, organizing your schedule, or simply double-checking, these techniques are easy, practical, and reliable.

Next time someone asks how many days are in a specific month, you’ll have two quick answers—both accurate and timeless. So, share these fun, old-school tricks and help others stay one step ahead!