National Climatic Data Center, 14 January 2003

• December Temperatures
• Temperature Departures
• Last 3 months (Oct-Dec)
• 12-month Temperatures (Jan-Dec)

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• U.S. Precipitation

December Temperatures

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The graph to the left shows monthly mean temperature averaged across the contiguous United States based on long-term data from the U.S. Historical Climatology Network (USHCN). The value for 2002 is estimated from preliminary Climate Division data using the first difference approach. December 2002 ranked as the 21st warmest December in the 1895 to present record. The preliminary nationally averaged temperature was 35.8° F (2.1° C) which was 2.4° F (1.3° C) above the long-term mean.

Much above average warmth occurred in 4 northern U.S. states in December with a ranking of 8th warmest December on record for Idaho, Montana and Minnesota, while Nebraska ranked 10th. Much of the remainder of the western half of the continental U.S. (15 states) was also warmer than average for the month. Only 4 southeastern states had significantly below average temperatures for December (FL, AL, GA and SC), with the rest of the lower 48 states averaging temperatures close to the long-term mean. As can be seen in a map of divisional temperature (below right), significantly cooler than average temperatures also extended northward through the mid-Atlantic states. The pattern of warmth and cold in the contiguous U.S. in December broadly corresponded with the mean 500mb height and anomalies chart. This shows that well above normal 500mb heights extended from Canada into the northern Great Plains, which were associated with the much above average temperatures in December. It was the 5th warmest December since reliable statewide records began in 1918 for Alaska , with anomalies of 4.9°F (2.7°C) above normal relative to the period 1971-2000.

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Regional Temperature Ranks for the
Contiguous U.S., December 2002

Region	Rank
Northeast	50th coldest / 59th warmest
East North Central	93rd coldest / 16th warmest
Central	65th coldest / 44th warmest
Southeast	34th coldest / 75th warmest
West North Central	102nd coldest / 7th warmest
South	64th coldest / 45th warmest
Southwest	74th coldest / 35th warmest
Northwest	99th coldest / 10th warmest
West	88th coldest / 21st warmest

Temperature Departures

The map below, based on over 500 airport stations, shows departures from the 1971-2000 normal temperatures for December 2002. In the lower 48 states, some of the largest widespread positive departures (greater than 7.5°F [4.2°C]) occurred in the Upper Mississippi Valley and Northern Great Plains. Most of the warmth in this region occurred around the middle of the month, and then again during the last few days of December (as can be seen in an animation of daily temperature anomalies).

A new maximum daily temperature record was set in Wichita Falls, KS on December 17th when the high reached 79°F (26.1°C) breaking the old December 17th maximum temperature of 77°F (25°C) set in 1980. Numerous other daily maximum temperature records were broken in the middle of the month over the central and north central areas of the country. However, Alaska had the largest monthly positive departures (greater than 9°F [5°C]) at many of its stations and additionally, many daily records were also being broken. McGrath, AK had its maximum daily temperature record shattered on December 3rd when the high reached 40 degrees (4.4°C). The previous high temperature for that date in McGrath was 30°F (-1.1°C) set in 1979.

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The East coast had generally lower than average temperatures for December 2002. Much of the coolness for the east coast was during the first 10 days of the month and many locations had record low temperatures during that time. For example, Jackson, KY reached a low of 20°F (-6.7°C) on December 1st, breaking the old December 1st minimum temperature record by 2 degrees Fahrenheit (1.1°C). See NCDC's Monthly Extremes web-page for more records.

October-December 2002

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The graph to the left shows mean temperature averaged across the contiguous United States based on long-term data from the U.S. Historical Climatology Network (USHCN). The value for October-December 2002 is estimated from preliminary Climate Division data using the first difference approach. October-December 2002 was very near average and ranked as the 55th warmest such period in the 1895 to present record. The preliminary nationally averaged temperature for October-December 2002 was 43.7° F (6.5° C) which was 0.1° F (0.06° C) above the long-term mean.

Six states (TX, OK, MO, PA, MA and ME) averaged somewhat cooler than normal from October-December, and 3 states(CA, NV and MT) were above normal. However, none of the contiguous U.S. states were much above or below normal averaged over the 3 months, October-December. While much of the country was cold in October, this was mostly balanced by above average warmth in December. November saw few monthly temperature extremes.

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National Temperatures - January-December 2002

A comprehensive annual assessment of the U.S. climate is available in preliminary form and will be in final form on January 23rd.
larger image	The graph to the left shows mean temperature averaged across the contiguous United States based on long-term data from the U.S. Historical Climatology Network (USHCN). January-December 2002 ranked as the 14th warmest such period in the 1895 to present record. The preliminary nationally averaged temperature was 53.9°F (12.2°C) which was 1.1°F (0.6°C) above the long-term mean.

Widespread warmth occurred across the country during 2002. For the second consecutive year, no state averaged significantly cooler than the mean. Twelve states ranked in the top ten warmest years in the 108-year record. The Northeast and Southwest Regions ranked as the 11th warmest on record.

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Questions?

For all climate questions other than questions concerning this report, please contact the National Climatic Data Center's Climate Services Division:

Climate Services Division NOAA/National Climatic Data Center 151 Patton Avenue Asheville, NC 28801-5001 fax: 828-271-4876 phone: 828-271-4800 email: questions@ncdc.noaa.gov

For further information on the historical climate perspective presented in this report, contact:

Catherine Godfrey NOAA/National Climatic Data Center 151 Patton Avenue Asheville, NC 28801-5001 fax: 828-271-4328 email: Catherine.S.Godfrey@noaa.gov

Jay Lawrimore NOAA/National Climatic Data Center 151 Patton Avenue Asheville, NC 28801-5001 fax: 828-271-4328 email: Jay.Lawrimore@noaa.gov

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