Climate Monitoring / Climate of 2006 / August / Help

Climate of 2006 - August in Historical Perspective


Including Boreal Summer


National Climatic Data Center
14 September 2006

Contents of this Report:

Selected Global Significant Events for August 2006
Map of Selected
Global Significant Events
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Major Highlights


U.S. HAS SECOND WARMEST SUMMER ON RECORD
ABOVE AVERAGE RAINFALL IN AUGUST EASES DROUGHT FOR SOME


Summer ended with the 11th warmest August on record for the contiguous United States and the 3-month summer season as the 2nd warmest on record. Combined with other unusually warm months this year, the year-to-date temperature climbed to its highest level since national records began in 1895. Above average rainfall in much of the central and southwestern U.S. in August led to improving drought conditions in some areas, but moderate to extreme drought continued to affect 40% of the nation, according to NOAA's National Climatic Data Center in Asheville, N.C.

U.S. Temperature Highlights
The average June-August 2006 temperature for the contiguous United States (based on preliminary data) was 2.4°F (1.3°C) above the 20th century average of 72.1°F (22.3°C). This was the second warmest summer on record, slightly cooler than the record set during the Dust Bowl year of 1936. Eight of the past ten summers have been warmer than average in the U.S. Not since the decade of the 1930's have summer temperatures been as warm as the most recent ten years in the U.S.

This year's summer heat was highlighted by an intense and long lasting heat wave which began in mid-July in the northern Plains and Upper Midwest, breaking records that stood since the Dust Bowl years in some locations. The heat spread across the Plains and moved into the West before returning to the northern Plains by late July, then spreading to the East Coast by the first week of August. More than 50 all-time high temperature records were established in the US during the last 2 weeks of July and several more during the first half of August.

The Residential Energy Demand Temperature Index (REDTI), which provides information related to climate sensitive residential energy demand, ranked as the 6th highest summer index in the 112-year record. Using this index, NOAA scientists determined that the nation's residential energy demand was approximately 10% higher than that which would have occurred under average climate conditions for the season.

The persistence of the anomalous warmth in 2006 made this January-August period the warmest on record, eclipsing the previous record of 1934. Six individual months were much warmer than average (within their top 10 warmest on record), with only February and March near average.

U.S. Precipitation Highlights
The record and near-record heat in many areas, combined with below average precipitation, led to worsening drought conditions throughout the spring and much of the summer for large parts of the country. But above average rainfall in August helped ease drought conditions in some of the most severely affected states.

An early and extremely active monsoon season in the Southwest gave New Mexico its wettest August on record, and precipitation in Arizona was also above average. Following the 2nd driest winter on record for the Southwest region that left snowpack levels extremely low and little spring runoff to fill reservoirs, the recent rainfall brought much needed drought relief to New Mexico and some parts of Arizona and west Texas. However, heavy downpours produced localized flooding across parts of the entire region.

Above average precipitation also fell across the Plains states into the Midwest as well as the Carolinas and parts of the Northeast in August. This helped reduce drought severity in other areas such as the Dakotas and parts of Oklahoma but was not sufficient to end drought in the most severely affected areas. At the end of August, 40% of the contiguous U.S. was in moderate to extreme drought (based on the Palmer Drought Index), a reduction of 9% since July.

However, drought conditions worsened in some parts of the country and dry conditions in the Northwest and northern Rockies helped keep the country on pace to a possible new record in number of annual acres burned by wildfires. Rainfall in August was below normal from Montana to southern California and the Pacific Northwest. This continuation of drier-than-average summer in the Northwest contributed to a large number of wildfires in late summer, and through early September the number of acres burned in the US neared the record of almost 8.7 million acres burned during all of 2005, according to the National Interagency Fire Center.

Global Highlights
It was the fourth warmest August on record for global land and ocean surface temperatures since records began in 1880 (0.97°F/0.54°C above the 20th century mean) and the third warmest boreal summer (June-August) (1.01°F/0.56°C).

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to the top Global Hazards and Significant Events


to the top National Overview


to the top United States Drought


to the top U.S. Pre-Instrumental Perspective

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Climate Monitoring / Climate of 2006 / August / Help