May 31 National Days

May 31 is the 151st day of the year (152nd in leap years) in the Gregorian calendar, leaving 214 days until the end of the year. Today’s observances cover a wide range of topics—from wildlife protection and mental wellness to coconut cookies and emerging technology.

National Days on May 31st — May 31st National Days

Most holidays on this day are fixed-date observances, but there is one moving-date celebration to note: National Caesar Day, which falls on the Thursday before Victoria Day in May.

Here’s a complete overview of the 15 national and international days celebrated on May 31.

National and International Days on May 31

Infidelity Hurts Awareness Day: Founded by Christina Renee, a member of the American Psychological Association, as a way to give voice to those affected by infidelity. She created the day to provide a safe and honest space for people to process their experiences without shame. Originally called Infidelity Speaks Awareness Day, the observance highlights the emotional damage caused by betrayal and challenges how infidelity is often downplayed in culture and relationships.

International Flight Attendant Day / International Cabin Crew Day: Honors the dedication and professionalism of flight attendants worldwide. Celebrated on May 31 since at least 2015, the day recognizes the crucial role these crew members play in passenger safety, comfort, and travel experience. It’s an opportunity to thank the people who guide us through takeoff, turbulence, and touchdown with care and calm.

National Autonomous Vehicle Day: Brings attention to the evolving world of self-driving technology. Celebrated since 2017, the day was founded by Emerging Prairie and Marlo Anderson to spotlight innovation in autonomous transport—from cars to drones. It marks a turning point in how we think about travel, commerce, and the future of mobility.

National Caesar Day* (Thursday before Victoria Day in May): Although it doesn’t always fall on May 31, this moving holiday deserves a mention when it does. Celebrated since 2015, National Caesar Day honors the iconic Canadian cocktail made with vodka, Clamato juice, Worcestershire sauce, hot sauce, and spices. The drink was invented in 1969 by Walter Chell, a bartender at the Calgary Inn (now the Westin Hotel). While it’s often compared to the Bloody Mary (celebrated on January 1st btw), the Caesar’s briny twist makes it uniquely Canadian.

🍸 Related celebrations include National Cocktail Day on March 24. For more alcohol-themed days, visit the dedicated article.

Necrotizing Fasciitis Awareness Day: Raises awareness about a rare but serious bacterial infection that can spread quickly through the body’s soft tissue. Often called a “flesh-eating disease,” necrotizing fasciitis requires early diagnosis and urgent treatment to prevent severe complications. This day has been observed annually on May 31 since 2017 to support education, prevention, and early intervention.

National Macaroon Day: Celebrates the small, chewy coconut cookie that’s often mistaken for its French cousin, the macaron. Traditionally made with almonds, egg whites, and sugar, the macaroon has been a Passover staple and a favorite treat for centuries. Its roots trace back to an 8th-century French monastery, and the cookie gained popularity thanks to two nuns in Nancy during the French Revolution. Over time, coconut became the signature ingredient in American-style macaroons.

National Save Your Hearing Day: Reminds us to take care of one of our most important senses. Observed every year on May 31, the day promotes awareness about noise-induced hearing loss and encourages protective habits, like using earplugs or turning down the volume. The goal is to prevent avoidable damage and preserve hearing throughout life.

National Smile Day: Established in 2018 by Dr. Tim Stirneman and Jim Wojdyla of Compassionate Dentalcare. Their goal was to highlight the power of a healthy smile to boost confidence and improve quality of life. The day encourages everyone to share a smile and acknowledge the emotional and physical benefits it brings.

National Speak in Complete Sentences Day: Celebrates the structure and clarity of language. Held annually on May 31, the day challenges people to use proper grammar and full sentences in everyday speech and digital communication. It’s a fun way to improve language skills while appreciating the importance of effective communication.

National Utah Day: Honors the 45th state to join the Union—Utah, admitted on January 4, 1896. Known as the Beehive State, Utah is celebrated for its stunning desert landscapes, Native American heritage, and unique geological landmarks like Arches National Park and the Bonneville Salt Flats. National Utah Day invites people to learn more about the region’s cultural history, natural beauty, and contributions to science and recreation.

What You Think Upon Grows Day: Created in 2002 by Stephanie West Allen, a lawyer and writer who wanted to promote the power of positive thinking. The observance falls on May 31 in honor of Norman Vincent Peale, a pioneer of the modern positive thinking movement. The day encourages focusing on thoughts that foster growth, gratitude, and mental well-being.

Web Designer Day: Observed annually on May 31, recognizes the creative professionals who build and shape our digital experiences. While its exact origins are unclear, the day acknowledges how far web design has come—from simple HTML pages to today’s interactive, user-centered websites. It’s a chance to thank the designers behind the screens for improving online functionality and aesthetics.

World Foster Day: Began in 2018 to raise awareness about the importance of foster care and to celebrate families who open their homes to children in need. Organized as part of broader campaigns like National Foster Care Month and Foster Care Fortnight, the day aims to educate communities and encourage greater support for vulnerable children across the globe.

World No Tobacco Day: Established by the World Health Organization in 1987, promotes global awareness about the dangers of tobacco use. Celebrated every May 31, the day calls for 24 hours of abstinence from tobacco and highlights the health risks it poses to smokers and non-smokers alike. Over 7 million deaths worldwide are linked to tobacco use each year, making this a critical public health observance.

No Smoking Habit Tracker (Printable PDF)

World Parrot Day: Launched in 2004 by the World Parrot Trust to spotlight the challenges parrots face in the wild and in captivity. The inaugural event included a rally in London’s Trafalgar Square and a petition to ban wild parrot imports to the European Union. The day promotes conservation efforts and celebrates the intelligence and diversity of these colorful birds—especially species like the African grey parrot, known for remarkable cognitive abilities.