Liigpäev

Liigpäev is a term used in some Scandinavian languages, including Swedish and Norwegian, to refer to a leap day. A leap day is an extra day added to the calendar in certain years to keep the calendar year synchronized with the astronomical year. This extra day is added at the end of February, making February have 29 days instead of the usual 28 in a leap year. The purpose of a leap day is to correct the discrepancy between the Earth's orbital period around the sun, which is approximately 365.2422 days, and the 365-day calendar year. Without leap days, the seasons would gradually drift out of sync with the calendar over time.

The Gregorian calendar, which is widely used today, specifies that a year is a leap year if it is divisible by four, except for end-of-century years, which must be divisible by 400. For example, the year 2000 was a leap year because it is divisible by 400, but 1900 was not a leap year because it is divisible by 100 but not by 400. This rule ensures that the calendar remains accurate over long periods. Therefore, a liigpäev occurs every four years, with the exception of the aforementioned century rule. This extra day is crucial for maintaining the accuracy of our timekeeping system.

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