Yes, every four years we add a day in February to compensate for the fact that it takes the Earth slightly longer than 365 days to orbit the Sun once (about 5 hours and 49 minutes longer). But did you know that every 100 years we donâ€™t have a leap year because by adding the extra day every four years we end up adding too much? Thereâ€™s one other exception to the rule. Every 400 years we do have a leap year.
Hereâ€™s the rule of thumb: If the year is divisible by 4, then itâ€™s a leap year. If the year is divisible by 100, then itâ€™s not a leap year. But, if the year is divisible by 400 then it is a leap year.