A leap year has 366 days, with an additional day added to February, making it 29 days instead of the usual 28
Leap years were introduced to align the calendar year with the time it takes Earth to complete its orbit around the Sun, which is approximately 365 days, 5 hours, 48 minutes, and 46 seconds
Scholars engaged by Julius Caesar introduced the leap year in 46 BC, with further precision added from 12 AD
Without leap years, crop cycles and seasonswould gradually drift, causing confusion and necessitating the periodic adjustment
The Julian calendar, used before the Gregorian calendar, added a 366th day every four years, but it wasn't error-free due to the slight difference in calculation
In the 16th century, Pope Gregory XIII addressedaccumulated errors by dropping 10 days from the calendar in 1582, adjusting October 4 to October 15
To address the calendar's drift, it was decided to skip some leap years, dropping them about once every century, with years ending in 00 posing a unique challenge
Leap years were not dropped uniformly for all years ending in 00. Only those divisible by 400, like the year 2000, were considered leap years in the Gregorian calendar
The Islamic calendar, Al-Hijra, also incorporates a leap year concept, adding an extra day to the 12th month Zul Hijja on leap years
Pope Gregory XIII's adjustments were a one-time action, and additional measures, like dropping some leap years, were implemented to fine-tune the calendar system