The Complete Guide to May's Obscure Holidays
May moves fully into spring — Cinco de Mayo, Star Wars Day's pun, and a genuine cluster of drink holidays (Cosmopolitan, Moscato, Mint Julep, National Wine Day) all land within the same few weeks. It's also one of the more tribute-heavy months, with dedicated days for Douglas Adams (Towel Day), Mark Twain (Frog Jumping Day), and Edward Lear (National Limerick Day).
This guide walks through all 63, day by day, with a bit of history or context for each one and a link to the full write-up — complete fun facts, ways to celebrate, and sourcing — on its own page.
Why does May have so many obscure holidays?
A striking number of May's holidays are literary or pop-culture tributes tied to a specific person's birthday, death, or published work — Towel Day for Douglas Adams, National Limerick Day for Edward Lear, Frog Jumping Day for Mark Twain, Twilight Zone Day for Rod Serling, Talk Like Yoda Day for Star Wars. The month also runs unusually drink-heavy, with cocktails, wine, and beverages generally claiming more dedicated days than in almost any other month.
How to use this guide
Holidays are grouped by date below. Each entry gets a short original write-up — not a repeat of the fact sheet — plus a link to the full holiday page if you want the deeper dive: complete fun facts, ways to celebrate, and sourcing.
May 1
🌺 Lei Day
Conceived in 1927 by poet Don Blanding, with the now-famous slogan “May Day is Lei Day” contributed by columnist Grace Tower Warren. Real etiquette applies here — it's considered rude to refuse a lei when offered. Full holiday page →
🌸 May Day
Carries two entirely separate identities on the same date: an ancient European spring fertility festival built around maypole dancing, and International Workers' Day, commemorating the 1886 Haymarket affair in Chicago. The U.S. deliberately moved its own Labor Day to September, partly to distance it from May Day's association with socialist and communist movements abroad. Full holiday page →
🎵 Tuba Day
Founded in 1979 by tubist Harvey Phillips specifically to recognize an instrument that rarely gets a solo — the tuba provides the bass foundation for orchestras and marching bands but almost never the melody. It's the largest and lowest-pitched instrument in the entire modern brass family. Full holiday page →
May 2
🔥 Fire Day
Humanity's controlled use of fire goes back over a million years, and it's hard to overstate the downstream effect — it reshaped diet, social structure, and how far early humans could migrate. Ancient cultures worldwide independently treated fire as something divine. Full holiday page →
🐟 World Tuna Day
Formally established by UN resolution in December 2016, with the first actual observance following in 2017. Bluefin tuna can swim in bursts up to 75 km/h, making them among the fastest fish in the ocean despite being warm-blooded, an unusual trait for fish generally. Full holiday page →
May 3
👟 National Two Different Colored Shoes Day
Created in 2009 by Dr. Arlene Kaiser with a single, specific goal: normalizing visible individuality rather than blending in. The entire premise is deliberately low-stakes — mismatched shoes as a small, easy act of standing out. Full holiday page →
👻 Paranormal Day
The word itself is just Greek prefix plus adjective — “para” (beyond) plus “normal” — a literal description rather than anything mystical. The category is broad enough to cover ghosts, UFOs, cryptids, and psychic phenomena all under one umbrella term. Full holiday page →
May 4
🐔 International Respect for Chickens Day
Chickens can recognize up to 100 different faces, human and chicken alike, and communicate through more than 20 distinct vocalizations — a level of social complexity most people don't associate with poultry. Established by United Poultry Concerns. Full holiday page →
⭐ Star Wars Day
The pun — “May the Fourth be with you” — actually predates the modern fan holiday by decades; the UK Conservative Party used it in a 1979 newspaper ad congratulating Margaret Thatcher on becoming Prime Minister. The first Lucasfilm-recognized celebration didn't happen until 2011, in Toronto. Full holiday page →
May 5
🇲🇽 Cinco de Mayo
Commonly mistaken for Mexico's Independence Day, which actually falls on September 16th — Cinco de Mayo instead marks a single, unlikely 1862 military victory at the Battle of Puebla, where an outnumbered, poorly equipped Mexican army beat a well-trained French force. It's a bigger holiday in the United States than in most of Mexico. Full holiday page →
🦪 Oyster Day
A single oyster can filter up to 50 gallons of water a day, making them a meaningfully positive presence for water quality wherever they're farmed. They also change sex over their lifetime, typically starting male and later becoming female. Full holiday page →
May 6
🥤 Beverage Day
Water and tea are, in that order, the two most consumed beverages on Earth — everything else, including coffee and soda, ranks below them globally. Coca-Cola and Pepsi both started out marketed in pharmacies as medicinal tonics. Full holiday page →
🍰 International No Diet Day
Founded in 1992 by British feminist Mary Evans Young, who built the day directly out of her own experience with eating disorders and diet culture. The light blue ribbon that symbolizes it is a smaller-scale, lesser-known cousin of more famous awareness ribbons. Full holiday page →
May 7
🍸 National Cosmopolitan Day
Went from cocktail-menu obscurity to global fixture almost entirely because of Sex and the City in the late 1990s. Bartender Cheryl Cook in Miami is often credited with inventing it in the mid-1980s, aiming to make a drink that looked beautiful in a martini glass. Full holiday page →
🍖 Roast Leg of Lamb Day
Technically only qualifies as “lamb” if the animal is under a year old — anything older is mutton, with a notably stronger flavor and tougher texture. The dish's association with spring goes back centuries. Full holiday page →
May 8
🥥 Coconut Cream Pie Day
Coconuts are botanically classified as a fibrous drupe, not a true nut — the same category as a peach or a plum, just with a much tougher husk. “Cream pie” specifically describes a custard filling assembled without further baking. Full holiday page →
🦶 No Socks Day
No documented founder or origin — just a grassroots, social-media-driven holiday that leans on warmer spring weather. Going sockless genuinely does reduce moisture and odor buildup. Full holiday page →
May 9
🧦 Lost Sock Memorial Day
Runs on the same premise as the internet's beloved “sock monster” theory — a shared, only-half-joking explanation for a mystery nobody's actually solved. The more mundane real explanations involve socks getting caught in the washing machine drum. Full holiday page →
🥂 National Moscato Day
Made from Muscat grapes, one of the oldest cultivated grape varieties in the world, with a documented history spanning thousands of years. Moscato d'Asti, the lightly sparkling version from Italy's Piedmont region, is the style most people picture. Full holiday page →
May 10
✨ Clean Up Your Room Day
A cluttered space is measurably linked to higher stress and reduced focus, which is the actual research behind what otherwise sounds like a nagging holiday. Making the bed each morning gets cited constantly by productivity researchers. Full holiday page →
🦐 Shrimp Day
There are more than 2,000 known shrimp species worldwide, living in both fresh and salt water. As decapods, they're close relatives of crabs and lobsters, and some species can flee predators by flexing their tail in a rapid backward “tail flip.” Full holiday page →
May 11
😋 Eat What You Want Day
Created by Thomas and Ruth Roy of Wellcat.com, a duo responsible for a surprising number of the internet's more whimsical unofficial holidays. The premise is explicitly framed around mindful indulgence, not just an excuse to abandon healthy eating outright. Full holiday page →
👁️ Twilight Zone Day
Marks Rod Serling's birthday. He personally wrote 92 of the original series' 156 episodes, an enormous workload for a single writer, and the show launched early appearances for future stars including William Shatner and Robert Redford. Full holiday page →
May 12
📝 National Limerick Day
Marks Edward Lear's birthday, whose 1846 “A Book of Nonsense” popularized the form — though Lear himself never actually called them limericks, preferring “nonsense rhymes.” Full holiday page →
🍫 Nutty Fudge Day
Fudge's popular origin story is genuinely an accident — a batch of caramel that crystallized wrong, reportedly first made by a Vassar College student in 1886. The name likely comes from a term meaning “a botched or clumsy job.” Full holiday page →
May 13
🐸 Frog Jumping Day
Marks the anniversary of Mark Twain's 1865 breakout short story, and Angels Camp, California still runs an actual competitive jumping-frog jubilee inspired by it. The all-time triple-jump record, 22 feet 7.5 inches, belongs to a frog fittingly named Rosie the Ribeter, set in 1986. Full holiday page →
🍸 World Cocktail Day
Marks the exact date, May 13, 1806, that the word “cocktail” got its first published definition, in a small Hudson, New York newspaper. That original definition is essentially still the technical template for an Old Fashioned. Full holiday page →
May 14
🐔 Dance Like a Chicken Day
The song actually originated in 1950s Switzerland as “Der Ententanz” — the Duck Dance, not the Chicken Dance — before American polka bands rebranded it in the late 1970s. Its largest recorded mass performance, at a 1994 Cincinnati Oktoberfest, drew roughly 72,000 participants. Full holiday page →
🦙 National Llama Awareness Day
Llamas can see nearly 360 degrees around themselves without turning their heads, an unusually wide field of vision built for spotting predators. A full-grown llama can weigh up to 450 pounds and stand 5 to 6 feet tall at the head. Full holiday page →
May 15
💐 Bring Flowers to Someone Day
Backed by real psychology: studies show receiving flowers produces a measurable mood boost that can last for several days, not just a momentary spike. Full holiday page →
🍪 National Chocolate Chip Day
The chocolate chip cookie was a genuine accident — Ruth Wakefield expected the chopped chocolate to melt smoothly into the dough at the Toll House Inn in 1938, and it simply didn't. Nestlé eventually acquired the rights to her recipe, paying her in a lifetime supply of chocolate rather than cash. Full holiday page →
May 16
🌳 Love a Tree Day
A single mature tree produces enough oxygen annually to support two people, a striking statistic for something that just stands still. Trees also share resources with each other through underground fungal networks researchers have nicknamed the “wood wide web.” Full holiday page →
☮️ Wear Purple for Peace Day
Entirely grassroots and social-media-driven, with no central organizing body behind it — distinct from the separate Purple Day for epilepsy awareness observed in March. Full holiday page →
May 17
📦 Pack Rat Day
The term comes directly from the Neotoma genus of actual woodrats, native to North America, which really do hoard shiny objects and trash alike in their nests. Full holiday page →
🍪 World Baking Day
The earliest known bread dates back roughly 14,400 years, baked by Natufian hunter-gatherers in what's now Jordan — bread predates farming itself. Ancient Egyptians were among the first to figure out yeast's leavening properties. Full holiday page →
May 18
🧼 No Dirty Dishes Day
The first commercially successful dishwasher was invented in 1886 by Josephine Cochrane, motivated less by convenience than by frustration — she was tired of her servants chipping her fine china by hand. Full holiday page →
👨👩👧👦 Visit Your Relatives Day
Research consistently links strong extended-family ties to better mental and emotional well-being, giving this otherwise generic-sounding holiday real backing. It's deliberately flexible about format. Full holiday page →
May 19
☀️ May-Ray Day
About as loosely defined as holidays get — no founder, no origin story, just a vague, pleasant association with increasing sunshine as May progresses. Full holiday page →
🌱 World Plant a Vegetable Garden Day
Half an hour of gardening burns roughly 150 to 200 calories, comparable to a brisk walk. Many common “vegetables” — tomatoes, cucumbers, peppers, peas — are technically fruits botanically, since they develop from the plant's flower and contain seeds. Full holiday page →
May 20
💰 Be a Millionaire Day
The word “millionaire” itself only entered the English language in 1816, relatively recent for a concept people now treat as timeless. By the end of 2022, the global millionaire population had passed 59 million people. Full holiday page →
🍓 Pick Strawberries Day
Timed to the peak of strawberry season, and botanically the fruit is unusual enough to deserve its own footnote: it's technically an “aggregate accessory fruit,” the only common fruit that carries its roughly 200 seeds on the outside. Full holiday page →
May 21
🩹 I Need a Patch for That Day
Patching clothing to extend its life predates modern fast fashion by centuries. The same word now applies just as often to software — a “patch” fixing a bug is a direct linguistic descendant of a patch fixing a torn sleeve. Full holiday page →
👽 Talk Like Yoda Day
Yoda's speech pattern has an actual linguistic name — Object-Subject-Verb syntax — which is genuinely rare across real human languages. Despite his prominence since 1980's The Empire Strikes Back, his species and home planet have never been officially revealed. Full holiday page →
May 22
🎵 Buy a Musical Instrument Day
The oldest known musical instruments are flutes carved from bird bone and mammoth ivory, found in Germany and dated to roughly 42,000–43,000 years ago. Learning an instrument is linked to measurable improvements in memory, coordination, and stress reduction. Full holiday page →
🦇 World Goth Day
Started in 2009 in the UK, growing out of a single BBC Radio 6 Music feature on goth music before expanding into an international observance. Its explicit goal from the start was correcting stereotypes about the subculture. Full holiday page →
May 23
🪙 Lucky Penny Day
The tradition specifically requires the penny to be heads-up — a tails-up penny is sometimes considered bad luck unless you flip it over for the next person to find. Full holiday page →
🐢 World Turtle Day
Founded in 2000 by American Tortoise Rescue, and turtles' evolutionary lineage stretches back over 200 million years. Their shell isn't a separate covering — it's fused directly to their skeleton, ribs and spine included, which is why a turtle can never actually leave it. Full holiday page →
May 24
🤝 Brother's Day
Often attributed to C. Daniel Rhodes of Alabama, though like many modern informal holidays the exact origin isn't rigorously documented. It deliberately complements National Siblings Day in April and National Sisters Day in August. Full holiday page →
🔍 National Scavenger Hunt Day
The modern scavenger hunt is often credited to 1930s socialite Elsa Maxwell, who built elaborate versions into her famously extravagant parties. Digital versions like geocaching have since extended the format into a GPS-based hobby. Full holiday page →
May 25
🍷 National Wine Day
The world's oldest known winery, discovered in Armenia's Areni-1 cave, dates back roughly 6,100 years — older than the pyramids. It takes about 2.5 pounds of grapes to produce a single standard 750ml bottle, and the fear of wine has an actual name: oenophobia. Full holiday page →
🌌 Towel Day
Falls exactly two weeks after Douglas Adams' death on May 11, 2001, and started organically on a fan forum called Binary Freedom rather than any official tribute. The premise comes straight from Adams' own text — a towel has “immense psychological value” for a hitchhiker. Full holiday page →
May 26
🍰 Blueberry Cheesecake Day
Cheesecake's history goes back to ancient Greece, where a version was reportedly served to athletes at the 776 BC Olympic Games for energy. Blueberries are one of the few fruits actually native to North America. Full holiday page →
✈️ National Paper Airplane Day
Leonardo da Vinci reportedly sketched and tested early paper and parchment flying models around 1488, centuries before the folded-paper airplane most people know. The indoor flight-duration world record, 29.2 seconds, was set by Takuo Toda in 2010. Full holiday page →
May 27
🩹 Cellophane Tape Day
Invented in 1930 by 3M engineer Richard Drew, who'd previously developed masking tape and pivoted the same adhesive concept into a transparent version. The “Scotch” brand name is rumored to trace back to a customer complaint accusing 3M of being stingy with adhesive. Full holiday page →
🧴 Sunscreen Day
The first commercially successful sunscreen dates to 1944, created by Florida pharmacist Benjamin Green. SPF specifically measures how much more UV exposure protected skin can handle before burning compared to unprotected skin. Full holiday page →
May 28
🥩 Brisket Day
The word traces back through Middle English to an Old Norse root meaning “cartilage,” a fittingly unglamorous etymology for a cut prized today for exactly the opposite reason. A full-packer brisket can take up to 18 hours to smoke properly. Full holiday page →
🍔 National Hamburger Day
The name likely traces to Hamburg, Germany, known for a fried minced-meat patty called Frikadeller, though the American sandwich itself is usually credited to Louis' Lunch in New Haven, Connecticut in 1900. Full holiday page →
May 29
📎 Paperclip Day
During World War II, Norwegians wore paperclips on their lapels as a quiet, deniable symbol of resistance against Nazi occupation, since displaying national symbols was banned outright. Full holiday page →
🪶 Put a Pillow on Your Fridge Day
No documented origin beyond internet-era word of mouth — the entire tradition is just placing a pillow on top of your refrigerator, with some claiming it brings good luck or financial fortune. Full holiday page →
May 30
💰 Loomis Day
An unusual entry: an unofficial nod to an actual cash-logistics company, not a folk tradition or invented joke. Loomis traces back to 1852, originally transporting gold and silver, and its armored trucks now move billions of dollars daily across more than 20 countries. Full holiday page →
🍹 National Mint Julep Day
The official drink of the Kentucky Derby since 1938, and Churchill Downs reportedly serves more than 120,000 of them over just the two days of Derby weekend. The word “julep” traces back to the Arabic gulab, meaning rosewater. Full holiday page →
May 31
🍪 Macaroon Day
Often confused with the French macaron, but the two are genuinely different desserts — the macaroon is coconut-based, the macaron almond-based, and only the name overlaps. Coconut macaroons are a popular Passover treat since they're naturally flourless. Full holiday page →
👂 Save Your Hearing Day
The hair cells in your inner ear that convert sound into electrical signals don't regenerate once damaged, which is why hearing loss from noise exposure is permanent rather than temporary. Sustained exposure above 85 decibels is enough to cause that damage over time. Full holiday page →
Frequently asked questions
How many obscure holidays are there in May?
63, spread across all 31 days — including Tuba Day, which floats to the first Friday of the month rather than a fixed date.
What's the most literary month on the calendar?
May has a real case for it — Towel Day (Douglas Adams), National Limerick Day (Edward Lear), and Frog Jumping Day (Mark Twain) all pay tribute to a specific author on a specific date.
Are there a lot of drink holidays in May?
Yes — National Cosmopolitan Day, National Moscato Day, World Cocktail Day, National Wine Day, and National Mint Julep Day all land in May, more concentrated than any other month.
Where can I find the full history and fun facts for each holiday?
Every holiday name in this guide links to its own dedicated page with a longer write-up, sourced fun facts, and ideas for how to celebrate.
About this guide
This guide is part of the Obscure Holiday Calendar project — the same database that powers the iOS and Android apps and the individual holiday pages on this site. It exists to give a single, readable overview of an entire month at once, instead of requiring 63 separate page visits.