Most people know that leap year happens every four years, but do they understand why? Surprisingly enough, leap years aren’t simply in place to harass “leaping” babies that they are actually 7 years old instead of 28; adding an extra day to the calendar serves a very real purpose to keep our beautiful world in check. So if you’re curious, or feeling a little guilty that you’re 34 and can’t exactly explain to your kiddo why leap year happens, don’t worry, we won’t tell. Read on for leap year 101 and learn some interesting tidbits along the way!
A Leap Day is an extra day on February 29th approximately every four years of the Gregorian Calendar, the most widely used civil calendar. A Leap Year is a year that contains that lovely extra little leap day.
How do we calculate leap years? If a year is divisible by 4, then it is a leap year (aka has that extra day). The exception is if it is a century year, such as 1900 or 2000, then it needs to be divisible by 400 to determine if it’s a leap year. For example, 1700 was not a leap year, but 2000 was; 2013 was not a leap year, but 2016 is.
So what’s the big deal, why do we need leap years? There are 365 days in a year, but it actually takes 365.2422 days for the Earth to orbit the sun. Essentially meaning, about 1/4 of a day is unaccounted for each year – so after 4 years, that day is made up on the leap year, keeping the calendar synchronized with our seasons.
Without leap days, the calendar is off about 5 hours, 48 minutes, 45 seconds each year; and while that doesn’t seem like a lot, it adds up quickly. For example, after 100 years, our seasons would be off by 25 days!
Now that you’re a leap year pro, go impress some friends with your new fun facts!