When it comes to quirky calendar phenomena, few are as intriguing as Thanksgiving’s latest possible date: November 28th. In the United States, Thanksgiving is always observed on the fourth Thursday of November, meaning it can never fall later than the 28th. This puts a firm deadline on when the holiday season kicks off, ensuring that Thanksgiving never slips into the last days of the month. Interestingly, this unique calendar twist means we can never have Thanksgiving on the 29th!
But that’s just the beginning of the interesting calendar oddities. Another one that brings a dash of magic, especially around Halloween, is the full moon falling on October 31st. This only happens roughly every 19 years, following what’s known as the Metonic cycle. A full moon on Halloween provides an extra dose of spookiness, as seen in the 1993 cult classic ‘Hocus Pocus,’ where the witches—the Sanderson sisters—are resurrected on a Halloween night with a full moon. The eerie celestial event last coincided with Halloween in 2020, setting the perfect backdrop for the release of ‘Hocus Pocus 2’ in 2022. Though the sequel arrived on Disney+ without the full moon, it still recaptured the whimsical chaos of the original film with returning stars Bette Midler, Sarah Jessica Parker, and Kathy Najimy, along with a fresh storyline.
In addition to these well-known phenomena, there are other intriguing quirks in our calendar:
Leap Year and February 29th
Every four years, we add an extra day—February 29th—to keep our calendar aligned with Earth’s orbit around the Sun. This means that “leaplings,” or those born on February 29th, get a “real” birthday only once every four years. But, did you know that century years (like 1900 or 2100) are typically not leap years unless they are divisible by 400? So, 2000 was a leap year, but 2100 won’t be, adding another layer to this peculiar phenomenon.
The “Missing Week” of 1582
When the Gregorian calendar was introduced, it needed to correct the drift that had developed over the centuries. This correction was achieved by skipping 10 days in October 1582. In some countries, October 4th was immediately followed by October 15th! The change wasn’t adopted everywhere at the same time, meaning the world essentially “lost” a week—creating a historical quirk with both astronomical and cultural implications.
Friday the 13th
Friday the 13th is often seen as unlucky, but did you know it can occur up to three times in a year? The 13th day of the month lands on a Friday whenever the 1st of that month is a Sunday. While this phenomenon might not seem significant on the surface, it’s enough to spawn superstition, movies, and an entire phobia—triskaidekaphobia—around the number 13.
February Starts and Ends on the Same Day
In non-leap years, if February 1st falls on a Monday, so does February 28th, creating a perfect four-week month that begins and ends on the same day. While not as dramatic as a full moon or Thanksgiving’s shifting dates, it’s still a satisfying quirk that adds to the charm of our 365-day cycle.
These calendar curiosities, from Thanksgiving’s shifting date to full moons, leap years, and missing days, show how human tradition and celestial patterns come together to shape the passage of time. Whether it’s a family feast, a spooky movie night, or a “real” birthday celebration every four years, these phenomena add a little wonder to our everyday lives. So next time you mark your calendar, remember there’s more than meets the eye—there might just be a bit of magic too!