It is a rare date today! February 29. Typically the year has just 365 days but 2024 is a leap year. So why do we have the extra day?

February sees 29 days instead of 28 as in "normal" years thanks to a calendar featuring 366 days.

The reason? Earth orbits the Sun in an average of 365 days, five hours, 48 minutes and 45 seconds. However, a calendar year lasts 365 days, creating a deficit. To compensate for this, there is a leap year every four years. However, this still does not perfectly capture the orbit around the sun.

A leap year is also set every 100 years, unless the centuries are divisible by 400, as in the year 2000. Our calendar is therefore ahead of its time, so to speak. This is also reflected in the earlier start date of the seasons.

From 2048, the astronomical start of spring will therefore even take place on 19 March. In 2100, a leap year will be skipped for the next time, so that from 2102 the start of spring will once again fall on March 21.

The different seasons are determined by the inclination of the earth's axis to the Sun's orbit. Until now, the Sun has been exactly at its zenith at the equator on March 20 or 21. In the coming years, it will usually be March 20 and later also March 19.

Therefore, leap years are essential for maintaining our regular seasonal weather conditions in the long-term.

Meteorological spring officially begins on March 1, check back tomorrow to celebrate its arrival and learn more on why there is a difference.