King Charles III, born on November 14, 1948, celebrated his “official birthday” in mid-June last Saturday with the traditional Trooping the Color parade in London’s St. James’s Park. This annual event features a military procession involving approximately 1,400 soldiers, who march in formation and display banners in honor of the monarch’s birthday. The choice to mark the royal birthday in summer, rather than on the actual November date, follows a tradition established by King Edward VII, who reigned from 1901 to 1910.

Edward VII, also born in November, introduced the practice of celebrating the monarch’s birthday during late spring or early summer to take advantage of better weather conditions. This adjustment aimed to ensure more favorable weather for the elaborate outdoor ceremonies like Trooping the Color, which might otherwise be hindered by the typically cold and gray British winter. Though Charles’s actual birthday remains November 14, official celebrations have shifted to a sunnier time of year, continuing a century-old royal custom.

The idea of celebrating birthdays at alternative times has spread beyond royal circles, with some individuals opting for half-birthday or “unbirthday” observances. Roberto Soto III, a Brooklyn DJ known as Mamma, experienced a difficult personal birthday six years ago, which involved moving out of his apartment under strained circumstances. Six months later, after positive changes in his life, he embraced his half-birthday as an opportunity for celebration. He transformed a bi-monthly comedy and dance event into an annual half-birthday party, featuring music genres such as Miami bass, Baltimore club, and pop.

Soto highlighted how half-birthday celebrations relieve the pressure often associated with birthdays, framing them as a more relaxed occasion. “With your birthday-birthday, I feel like there’s a lot of pressure,” he said. “A half birthday, on the other hand, is just another day.”

The appeal of birthday observances varies widely, especially for those born on major holidays or at inconvenient times of year. For example, children born on December 25 often share celebrations with Christmas festivities, making standalone birthday parties less common. This overlap can lead some to seek alternative celebrations, such as half-birthdays in summer months, which accommodate warmer weather and more social availability.

Data from the digital invitation platform Partiful indicates that alternative birthday celebrations are gaining popularity. In the past year, over 40,000 individuals RSVP’d to events labeled as “half birthday” or “unbirthday.” Upcoming examples include a July “Christmas in July Half Birthday BBQ” for a child with a late-December birthday, a “Half Birthday Silent Retreat” scheduled for April, and a “Unbirthday Bonfire” planned in California.

The concept of the “unbirthday” has literary roots dating back to Lewis Carroll’s 1871 novel “Through the Looking-Glass.” In the story, the character Humpty Dumpty explains the idea of unbirthday presents—gifts given on any of the other 364 days of the year besides one’s actual birthday. This notion has also been popularized by Disney’s animated adaptation of “Alice in Wonderland,” featuring a whimsical unbirthday tea party.

Royal experts emphasize that monarchs continue to observe their actual birthdays in more private manners, accompanied by formal rites such as gun salutes and official announcements. According to biographer Robert Hardman, the real birthday includes “various gun salutes” and the playing of the national anthem on radio broadcasts, alongside the public summer festivities.

Ultimately, the practice of celebrating birthdays on a preferred date offers flexibility and can enhance enjoyment, whether for royalty or the public, providing an opportunity to honor special occasions under more favorable circumstances.