NCDC reports warmest year on record for U.S.

News
Jan 11, 2013

It’s official; the National Climatic Data Center (NCDC) has confirmed 2012 was hot! In fact, for 19 U.S. states, it was record breaking hot.

According to NCDC and National Oceanic and Atmospheric Administration scientists, the average temperature for the contiguous U.S. for 2012 was 55.3° F, which was 3.2° F above the 20th century average and 1° F above the previous record from 1998. The year consisted of the fourth warmest winter, a record warm spring, the second warmest summer, and a warmer-than-average autumn. Although the last four months of 2012 did not bring the same unusual warmth as the first eight months of the year, the September through December temperatures were warm enough for 2012 to remain the record warmest year, by a wide margin.

The average precipitation total for the contiguous U.S. for 2012 was 26.57 inches, 2.57 inches below average, and the 15th driest year on record for the nation.

Every state in the contiguous U.S. had an above-average annual temperature for 2012. Nineteen states had a record-warm year, and an additional 26 states had one of their 10 warmest. On the national scale, 2012 started off much warmer than average, with the fourth-warmest winter (December 2011–February 2012) on record. The winter snow cover for the contiguous U.S. was the third smallest on record, and snowpack totals across the central and southern Rockies were less than half of normal.

Spring started off exceptionally warm, with the warmest March on record, followed by the fourth-warmest April and second-warmest May. The season’s temperature was 5.2° F above average, easily the warmest spring on record, surpassing the previous record by 20° F. The warm spring resulted in an early start to the 2012 growing season in many places, which increased water demand on the soil earlier than what is typical. In combination with the lack of winter snow and lingering dryness from 2011, the record-warm spring laid the foundation for the great drought of 2012.

The above-average temperatures of spring continued into summer. The national-scale heat peaked in July, which had an average temperature of 76.9° F, 3.6° F above average and the hottest month ever observed for the contiguous U.S. The eighth-warmest June, record-hottest July, and a warmer-than-average August resulted in a summer average temperature of 73.8° F—the second-hottest summer on record. An estimated 99.1 million people—nearly one-third of the nation’s population—experienced 10 or more days of summer temperatures greater than 100° F.

Autumn and December temperatures were warmer than average, but not of the same magnitude as the three previous seasons. Autumn warmth in the western U.S. was balanced by cooler temperatures in the eastern half of the country, while December was warmer than average for the east. Although the last four months of 2012 did not bring the same unusual warmth as the first eight months of the year, the September through December temperatures were warm enough for 2012 to remain the U.S.’ record-warmest year by a wide margin.

The U.S. Climate Extremes Index indicated that 2012 was the second most extreme year on record for the nation, according to NCDC. The index, which evaluates extremes in temperature and precipitation, as well as land-falling tropical cyclones, was nearly twice the average value and second only to 1998. — Traci Eatherton, WLJ Editor

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