In a typical year, tallying up the days from January to December in a calendar would sum up to 365 days. However, about every four years, February extends to 29 days instead of the usual 28. According to NASA, the Earth requires approximately 365.242 days to complete one orbit around the sun. It’s important to note the .242 part, an extra quarter of a day, around six hours each year, but for the sake of simplicity, this fractional day is conventionally rounded down to 365 days.

Those leftover six hours might not seem like a lot, but after four years, they pile up to a whole extra day, 24 hours! This accumulation prompts compensating for the surplus day to ensure chronological accuracy. Neglecting this adjustment could lead to a shift in seasons. Following 2024, February will have 29 days in 2028 and 2032.

To learn more about why leap year, visit NASA- Doing the Math on Why We Have Leap Day.