Why do we have a leap year every four years?
Quick Answer: We have a leap year every four years to keep our calendar aligned with Earth’s orbit around the Sun. Since a year is about 365.25 days, adding an extra day every four years fixes the extra quarter day and prevents the calendar from drifting out of sync with the seasons.
The Earth takes roughly 365.24 days to orbit the Sun, not a perfect 365. Our calendar uses 365 days, so those extra 0.24 days add up over time. Without correction, the calendar would slowly shift, making seasons fall on different dates.
By adding one extra day every four years, we catch up with this time difference. This day is February 29, giving us a leap year. This system keeps our calendars and seasons in harmony for the long run.