Yellow Pig Day

Yellow Pig Day is observed each year on July 17 and is dedicated to the number 17. This quirky holiday grew out of a playful tradition among math-minded friends who paired their favorite number with an equally odd symbol: a yellow pig. Whether you enjoy math or simply like offbeat celebrations, it is an easy excuse to have fun with numbers and a bit of harmless silliness.

History of Yellow Pig Day

Yellow Pig Day is often traced to mathematicians David Kelly and Michael Spivak, who popularized the tradition during their student years. The number 17 became the centerpiece of the celebration, and the “yellow pig” mascot was described with 17 features, most famously 17 eyelashes. What started as an inside joke eventually spread more widely, and July 17 became the natural date for the holiday because of the number itself.

Interesting Facts About Yellow Pig Day

The number 17 shows up in many different places, although some claims are more folklore than firm historical fact.

• The number 17 appears in many religious and cultural references, and some people enjoy tracking where it shows up in familiar texts and traditions.
• Some writers connect 17 with the French Revolution through number play involving the year 1789, although this is more a curiosity than a standard historical symbol.
• In Italy, 17 is sometimes considered unlucky because the Roman numeral XVII can be rearranged to form “VIXI,” a Latin word linked with the idea of life being finished.
• The fear of the number 17 is sometimes called heptadecaphobia.

For Yellow Pig Day, the point is less about proving every claim and more about enjoying the theme.

How to Take Part in Yellow Pig Day

Yellow Pig Day is best observed in a playful, low-stakes way. Draw a yellow pig, look for the number 17 in everyday life, or do a few quick math puzzles. You can also make the day a small tradition by using 17 of something, such as 17 candies, 17 minutes of a game, or 17 questions in a trivia round. If you share your celebration online, keep it light and use the hashtag #NationalYellowPigDay.

When Is Yellow Pig Day in 2026?

Yellow Pig Day is observed on July 17 each year.

Observations