Happy Leap Day! There’s an extra day tacked on to the end of February this year. Leap years happen every 4 years so our calendars stay in sync and avoid seasonal drift.
Why? The Earth takes 365 1/4 days to orbit the Sun. The Roman calendar year was 355 days long and based on the lunar cycle. The Moon completes an orbit around the Earth every 29.5 days or about a month, or Moonth.
When the seasons started to drift, they switched to the Egyptian solar calendar with 365 days, but added a leap year every 4 years to account for the 1/4 day. In the late 1500s, people realized they needed to drop 3 leap years every 400 years to make it even more accurate.
Enjoy the extra day of the year, it won't happen again until 2028.