How often have you wondered - why does February 29th come only once in four years? For all those who don't know - the Gregorian calendar, the most widely used across the globe, measures a year to be 365 days following the Earth's orbit around the Sun. However, the earth's orbit takes 365.24 days to complete its solar orbit and an extra day every four years is added to keep calendar seasons synchronised with solar seasons. February was chosen as the month to have the leap day as it is the only month without 30 or 31 days. Watch this video to learn more about the leap year story and the history behind February 29.