While much of Washington still slept Saturday morning, perhaps burrowing under an extra quilt, meteorological history was being made. It was not merely that the mercury sank to 26 degrees, matching the record for Washington's coldest Nov. 11.

It was also the first time in this cold weather season that the mercury in Washington, as measured at Reagan National Airport, had plunged below freezing.

More significantly, it was the first time that a record for lowest temperature had been set or matched in Washington for any date in November in this century.

Nor has a coldest-day record been set here this century in December or January, either.

By contrast, the record books almost bristle with hot day records set in Washington this century in those months.

In November, hottest-day records have been set or matched in Washington this century on six different dates. In December, the figure is 8; in January, 5. Records go back to 1871.