Century leap year

A century leap year in the Gregorian calendar is a year that is exactly divisible by 400 (and, thus, as with every other leap year, qualifies for the intercalation of February 29): other century years (with number divisible by 100 but not by 400) are common years. The years 1600 and 2000, for example, were century leap years; the century years of 1700, 1800, and 1900 were common years. The next century leap year will occur in 2400. Century leap years always start on a Saturday, and the February 29 intercalation of such years is always a Tuesday.

The century year "divisible by 400" rule of the Gregorian calendar was considered an improvement over the previously utilized Julian calendar which had provided for a leap year every four years; this practice resulted, over the centuries, in too many leap days being added to the calendar and placing it out of step with the astronomical seasons.

See also

• Calendar reform

References

• Spofford, Thomas (1835). A new system of practical astronomy: made plain and easy to those who have not studied mathematics : containing the elementary principles of the science, all the rules and tables necessary for making all the calculations for an almanac ... Boston: Lemuel Gulliver. p. 28.

External links

• An Introduction to Calendars courtesy of the United States Naval Observatory
• Frequently Asked Questions about Calendars
• History of Gregorian Calendar