Life's Little Mysteries

Why Do We Need Leap Year?

leap year, february
Leap year is necessary because it takes just less that 365 days to get around the sun. (Image credit: Calendar image via Feng Yu | Shutterstock)

Those of you who get paid every other Friday might get three paychecks this month. It's rare for that to happen in February, which normally has only 28 days and struggles to create five Fridays. It happened last in 1908 and won't come again until 2036.

The reason, of course, is that Friday, Feb. 29 is the day this year, like every fourth year, that we leap to fix the calendar. Why do we need to? Because Earth's trip around the sun is about 365.2422 days long, not the 365 that we've deemed to be a year. Every four years, we add 0.2422 x 4.

Did you know that every few years, a "leap second" is added to make up for the slowing down of the Earth's rotation? That last happened in 2005.

Robert Roy Britt

Robert is an independent health and science journalist and writer based in Phoenix, Arizona. He is a former editor-in-chief of Live Science with over 20 years of experience as a reporter and editor. He has worked on websites such as and Tom's Guide, and is a contributor on Medium, covering how we age and how to optimize the mind and body through time. He has a journalism degree from Humboldt State University in California.