Feb. 6, 2013 ? In 2012, the contiguous United States (CONUS) average annual temperature of 55.3?F was 3.2?F above the 20th century average, and was the warmest year in the 1895-2012 period of record for the nation. The 2012 annual temperature was 1.0?F warmer than the previous record warm year of 1998. Since 1895, the CONUS has observed a long-term temperature increase of about 0.13?F per decade. Precipitation averaged across the CONUS in 2012 was 26.57 inches, which is 2.57 inches below the 20th century average. Precipitation totals in 2012 ranked as the 15th driest year on record. Over the 118-year period of record, precipitation across the CONUS has increased at a rate of about 0.16 inch per decade.
On a statewide and seasonal level, 2012 was a year of both temperature and precipitation extremes for the United States. Each state in the CONUS had annual temperatures which were above average. Nineteen states, stretching from Utah to Massachusetts, had annual temperatures which were record warm. An additional 26 states had one of their 10 warmest years. Only Georgia (11th warmest year), Oregon (12th warmest), and Washington (30th warmest) had annual temperatures that were not among the ten warmest in their respective period of records. A list of the annual temperatures for each of the lower-48 states is available here. Numerous cities and towns were also record warm during 2012 and a select list of those locations is available here. Each state in the CONUS, except Washington, had at least one location experience its warmest year on record. One notable warmest year record occurred in Central Park, in New York City, which has a period of record dating back 136 years.
Much of the CONUS was drier than average for the year. Below-average precipitation totals stretched from the Intermountain West, through the Great Plains, into the Midwest and Southeast. Nebraska and Wyoming were both record dry in 2012. Nebraska's annual precipitation total of 13.04 inches was 9.78 inches below average, and Wyoming's annual precipitation total of 8.08 inches was 5.09 inches below average. New Mexico, Colorado, Kansas, Missouri, Illinois, Arkansas, Georgia, and Delaware had a top ten dry year. The large area of dry conditions in 2012 resulted in a very large footprint of drought conditions, which peaked in July with about 61 percent of the CONUS in moderate-to-exceptional drought, according to the Palmer Drought Severity Index (PDSI). The footprint of drought during 2012 roughly equaled the drought of the 1950s which peaked at approximately 60 percent. Wetter-than-average conditions were present for the Northwest, where Washington had its fifth wettest year on record. Washington's statewide precipitation total of 47.24 inches was 10.40 inches above average. Wetter-than-average conditions were also present across parts of the Gulf Coast and Northeast.
Seasonal highlights in 2012 include the fourth warmest winter (December 2011-February 2012), with warmer-than-average conditions across a large portion of the country. The largest temperature departures from average were across the Northern Plains, Midwest, Mid-Atlantic, and Northeast. Winter was drier than average for the East and West coasts, while the Southern Plains were wetter than average improving drought conditions across New Mexico, Oklahoma, and Texas. The warmer and drier than average conditions resulted in the third smallest winter snow cover extent on record for the contiguous United States. Spring (March-May) was record warm for the country, with 34 states being record warm for the period. The season consisted of the warmest March, fourth warmest April, and second warmest May on record. Spring precipitation was near-average for the lower-48, with the Pacific Northwest and Upper Midwest being wetter than average, while the Central Rockies and Ohio Valley were drier than average. The summer (June-August) continued the warmer-than-average trend for the contiguous U.S. with national temperatures ranking as the second warmest on record. The summer average temperature for 2012 was very close to the warmest summer (2011) and the third warmest summer (1936), with only 0.1?F separating the three. The summer season consisted of the eighth warmest June, record warmest July, and 13th warmest August. Drier-than-average conditions were anchored in the central U.S. with record breaking wildfires and a drought footprint comparable to the drought episodes of the 1950s causing large-scale agriculture problems in the Midwest, Plains, and Mountain West. Autumn (September-November) temperatures were closer to average compared to the preceding three seasons, but still ranked as the 22nd warmest autumn on record. Warmer-than-average conditions were present for the West, while cooler-than-average conditions were present for the Eastern Seaboard. Precipitation totals for the nation averaged as the 22nd driest autumn on record.
This annual report places the temperature and precipitation averages into historical perspective, while summarizing the notable events that occurred in 2012.
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