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Y2K-1 Will Arrive A Bit Late

If you’re already counting down to Y2K, don’t forget to add an extra second this New Year’s Eve.

The folks who decide these things have decreed that there shall be a leap second on Dec. 31, 1998, to keep our clocks synchronized to the spin of the Earth.

America’s timekeepers—the National Institute of Standards and Technology in Boulder, Colo., and the U.S. Naval Observatory in Washington, D.C.—will make this adjustment along with all other keepers of precise time around the world. Leap second decisions are made by the International Earth Rotation Service and the International Bureau of Weights and Measures.

Ever since 1972, when the world began keeping Coordinated Universal Time (known by its French abbreviation of UTC) instead of Greenwich Mean Time, our clocks have been gaining on the Earth. To keep them in step, an extra second has to be inserted from time to time, allowing the laggard Earth to catch up. If such adjustments were not made, after 10,000 years or so we would notice our clocks reading noon just as the sun was coming up.

The last leap second was added on June 30, 1997, and the 22nd one in the series will be inserted on Dec. 31, 1998, at 7 p.m. Eastern time (6 p.m. Central time, 5 p.m. Mountain time, and 4 p.m. Pacific time). The extra second will make the last minute before the hour a total of 61 seconds long.

As a non-regulatory agency of the U.S. Department of Commerce's Technology Administration, NIST promotes economic growth by working with industry to develop and apply technology, measurements and standards through four partnerships: the Measurement and Standards Laboratories, the Advanced Technology Program, the Manufacturing Extension Partnership and the Baldrige National Quality Program.

Released December 23, 1998, Updated November 27, 2017