Which years between 1970 and 2010 are considered leap years?

Holidays & Special Events

By Kristy Tolley

What are leap years?

Leap years are those that contain an extra day, added to the month of February, making it 29 days instead of the usual 28. This additional day is necessary because the Earth takes approximately 365.24 days to complete a full orbit around the sun, which means that without the additional day, the calendar would eventually fall out of sync with the Earth’s orbit. Leap years ensure that the calendar stays aligned with the astronomical seasons.

The 4-year rule of leap years

The rule for determining leap years is to add an extra day to the calendar every four years. This rule applies to all years that are evenly divisible by four. For example, 2000 was a leap year because it is divisible by four, while 1900 was not a leap year because, although it is a multiple of 4, it is also a century year.

Leap years in the 1970s: 1972 and 1976

The 1970s saw two leap years – 1972 and 1976. These years were divisible by four, making them eligible for the extra day in February.

Leap years in the 1980s: 1980 and 1984

The 1980s also had two leap years – 1980 and 1984. Again, these years were divisible by four, meeting the criteria for a leap year.

Leap years in the 1990s: 1992 and 1996

The 1990s were no exception to the four-year cycle, with two leap years in the decade – 1992 and 1996. As with the previous decades, these years were divisible by four.

Leap years in the 2000s: 2000, 2004, and 2008

The 2000s saw three leap years – 2000, 2004, and 2008. These years are divisible by four and follow the four-year rule.

Exceptions to the 4-year rule: century years

Although a leap year happens every four years, there are exceptions to this rule. Century years (i.e., years ending in 00) are not leap years, even if they are divisible by four.

Leap year in 2000: an exception to the exception

However, there is an exception to the exception. In every 400 years, there will be a leap year in a century year. 2000 was such a year, making it a leap year despite being a century year.

Leap year in 2100: a non-leap year

The year 2100 will be a century year and will not be a leap year. This is because it is not divisible by 400, making it ineligible for the extra day in February.

Leap years and the Gregorian calendar

Leap years were introduced in the Julian calendar, which had a slightly different leap year rule. The Gregorian calendar, which is the one currently in use, modified the Julian rule to align more accurately with the Earth’s orbit. The Gregorian leap year rule is the four-year rule with the exception of century years, as mentioned earlier.

Conclusion: A predictable pattern of leap years

Leap years are a necessary tool to keep our calendars in sync with the Earth’s orbit. Their pattern is predictable, following the four-year rule with exceptions for century years and special exceptions for years divisible by 400. By understanding this pattern, we can plan our schedules and events accordingly for the next century and beyond.

References and further reading

  • "Leap Years" by the National Institute of Standards and Technology (NIST)
  • "The Leap Year as a Metonic Cycle in the Gregorian Calendar" by the United States Naval Observatory (USNO)
  • "Leap Year" by Encyclopedia Britannica
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Kristy Tolley

Kristy Tolley, an accomplished editor at TravelAsker, boasts a rich background in travel content creation. Before TravelAsker, she led editorial efforts at Red Ventures Puerto Rico, shaping content for Platea English. Kristy's extensive two-decade career spans writing and editing travel topics, from destinations to road trips. Her passion for travel and storytelling inspire readers to embark on their own journeys.

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