Last month was the coolest January since 1994, according to scientists at NOAA’s National Climatic Data Center  (NCDC) in Asheville, N.C.
Across the contiguous United States, the average January temperature was 30.0 F, which is 0.8 F below the 1901-2000 average. And despite several large winter storms across the country, last month was the ninth driest January on record, much drier than normal. Average precipitation across the contiguous United States was 1.48 inches, 0.74 inch below the 1901-2000 average.
This monthly analysis, based on records dating back to 1895, is part of the suite of climate services NOAA provides.
U.S. Climate: January Highlights
• Cooler-than-normal conditions dominated most areas east of the Rocky Mountains, while the western coastal states of California, Oregon and Washington had above-normal temperatures in January.
• Several winter storms struck the northeastern U.S. during January, breaking January snowfall records in New York City and Hartford, Conn. Hartford’s Bradley International Airport broke the city's record for all-time snowiest month with 57 inches.
• The snowstorm that traversed the northern plains, Great Lakes and Northeast on January 9-13 was a Category 3, or “Major” snowstorm, according to preliminary analysis on the Northeast Snowfall Impact Scale (NESIS). The NESIS score of 5.31 was slightly greater than the “Christmas 2010” blizzard and slightly less than the storm of late February 2010. This storm also affected the Southeast and ranked as a Category 2, or “Significant” snowstorm, based on preliminary analysis of NOAA’s Regional Snowfall Impact Scale.
• As of Feb. 1, 24.1 percent of the United States was affected by moderate-exceptional drought. At this point last year, only 8.5 percent of the United States was affected. Some rain improved drought conditions across Virginia and Southern Illinois, while conditions worsened across the southwest desert into southwestern Texas.
• New Mexico set a record for driest conditions (0.55 inches of below normal precipitation), while Arizona and Nevada had their second driest January. Notably, Nevada’s extreme dryness followed a record-wet December for the state. Other states also experiencing much below normal precipitation averages were: Virginia (fifth driest), Oklahoma (eighth), North Carolina (ninth) and California (10th). Meanwhile, much-above normal precipitation fell in North Dakota and Nebraska.
Regional weather patterns
• Regionally, last month tied with 2003 as the driest January on record for the Southwest . Its January precipitation of 0.23 inches was nearly 0.7 inches below the 20th century average. The West  also had very low precipitation, resulting in its eighth-driest January.
January precipitation "statewide ranks" maps are available at the NCDC site .
U.S. Climate: Three and Twelve-Month Trends
• The Southeast experienced its seventh coolest November-January period on record. Five states had near-record cool temperatures: Georgia (fourth coolest), North Carolina (fifth), South Carolina (sixth), Florida (eighth) and West Virginia (ninth).
• From February 2010-January 2011, average temperatures set records for warmth in Maine (3.5 F above normal), New Hampshire (3.1 F above normal) and Rhode Island (3.1 F above normal and tied with 2002). Eight other states in the Northeast and Great Lakes areas averaged a temperature for the period among their 10 warmest. The Northeast  experienced its fourth warmest such period.
• January extended a pattern of continued dryness and expanding drought across a wide band of the southern United States. Four states experienced record drought for the November-January period: North Carolina (third), South Carolina (fourth), Arkansas (seventh) and New Mexico (ninth). Average precipitation in Montana (eighth wettest) and North Dakota (10th wettest) was much above normal.
• From February 2010-January 2011, the Southeast climate region  had its 10th driest 12-month period on record. Within the climate region, Georgia and South Carolina had their seventh and eighth driest such periods, respectively. The South was also very dry: Arkansas (fourth driest), Louisiana (seventh) and Mississippi (ninth). In contrast, many northern locations have seen a very wet 12-month period. North Dakota (6.3 inches above normal) had its wettest such period, while Iowa (11.6 inches above normal) and Minnesota (7.8 inches above normal) had their second wettest.
NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.