A leap year adjustment is a mechanism used in the Gregorian calendar to ensure the calendar year stays in sync with the astronomical year. This is done by adding an extra day, February 29, every four years to compensate for the fact that a solar year is approximately 365.2425 days long, not the calendar-standard 365 days.

Leap Year Adjustments

Leap Year Adjustment

Mechanism used in the Gregorian calendar

A calendar year is a one-year period that begins on January 1st and ends on December 31st, used for organizing schedules, events, and accounting in most of the world. It aligns with the Gregorian calendar, which is the internationally accepted civil calendar, and plays a crucial role in timekeeping, planning, and cultural observances.

Calendar Year

An astronomical year, also known as a sidereal year, is the time it takes for Earth to complete one orbit around the Sun relative to fixed stars, approximately 365.25636 days. This period is slightly longer than a calendar year due to Earth's axial precession and orbital dynamics, affecting the alignment of seasons over millennia.

Astronomical Year

Extra day

February 29

Every four years

A solar year, also known as a tropical year, is the time it takes for the Earth to complete one orbit around the Sun, measured relative to the equinoxes, averaging about 365.242 days. This period is fundamental to the Gregorian calendar, which is designed to align with the solar year to ensure seasonal consistency over long periods.

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