WASHINGTON - The National Climatic Data Center (NCDC) has announced that the 2006 average annual temperature for the contiguous United States was the warmest on record and nearly identical to the record set in 1998. Based on preliminary data, the 2006 annual average temperature was 55°F - 2.2° above the 20th century mean and 0.07° warmer than 1998.

It was originally estimated in mid-December that the 2006 annual average temperature for the contiguous U.S. would likely be 2° above the 20th century mean, which would have made 2006 the third warmest year on record, slightly cooler than 1998 and 1934, according to preliminary data. Further analysis of annual temperatures and an unusually warm December caused the change in records.

These values were calculated using a network of more than 1,200 U.S. Historical Climatology Network stations. These data, primarily from rural stations, have been adjusted to remove artificial effects resulting from factors such as urbanization and station and instrument changes which occurred during the period of record.

NCDC also noted that the past nine years have all been among the 25 warmest years on record for the contiguous U.S., a streak that is unprecedented in the historical record.

Publication date: 01/15/2007