Sept. 15, 2003 — Across the United States, temperature and rainfall during summer 2003 fluctuated by region. Much of the East was wetter and cooler than average, while most of the West sweltered under near-record high temperatures. Less-than-average rainfall in parts of the West led to worsening drought conditions, especially in the Northwest. Global surface temperatures were second warmest for the June-August period, and second warmest for August, according to scientists at the NOAA National Climatic Data Center in Asheville, N.C.

NOAA reported that the average temperature for the contiguous United States for the June to August summer season (based on preliminary data) was 72.5 degrees F (22.5 degrees C), which was 0.4 degrees F (0.2 degrees C) above the 1895-2003 mean. Although this is near average nationally, it resulted in a strong contrast in temperatures, with the West above normal and the East below normal. In August, warmth spread further east and the average national temperature for the month was 74.9 degrees F (23.8 degrees C), which was 2.1 degrees F (1.2 degrees C) above the 1895-2003 mean. This was the fifth-warmest August since national records began in 1895.

A dominant high pressure area persisted throughout the summer, triggering a barrage of daily and monthly all-time high temperature records across the West. The seasonal mean temperature in eight western states was much warmer than average, including Nevada, which had its warmest summer on record. Three states (Idaho, Nevada and Wyoming) also had their warmest August on record, while 10 other states in the northern tier of the U.S. had much above average temperatures for the month.
The Western warmth contrasted sharply with cooler-than-average temperatures recorded in much of the East for the summer season. Seven states from Mississippi to West Virginia were much cooler than average during June-August. This contributed to a rank of sixth-coldest summer for the Southeast region.

There was also a sharp difference in summer rainfall totals across the United States. Fourteen states in the eastern half of the country were significantly wetter than average for June-August, with both West Virginia and Pennsylvania having their second
wettest summer on record.

The same ridge of high pressure that brought record heat to the West during the summer also resulted in below-average precipitation in some states. Twelve states were significantly drier than average for June-August. Four of those states (Washington, Montana, Oregon and New Mexico) were much drier than average, and Washington had its driest summer on record. The dryness helped to ignite an active fire season during July and August in the Northwest and northern Rockies affecting Glacier National Park and Flathead National Forest. August saw the dryness extend into the Upper Mississippi Valley with Minnesota, Wisconsin and Iowa all having a much
drier-than-average month. Waterloo, Iowa, had its driest August on record with only 0.08 inches (2 mm) of rain falling during the month.

The unusual heat and lack of precipitation occurred in many of the same states that have experienced drought for the past three to five years. At the end of August, 36 percent of the contiguous U.S. was in moderate-to-extreme drought, based on a widely used measure of drought, the Palmer Drought Index. This was an increase of approximately five percent since July and 14 percent since the end of June. Deteriorating drought conditions during the summer were a reversal of a short-term trend toward improving conditions that had begun late last year. The persistence of unusually warm and dry conditions over the last several years has created conditions that rival those experienced during the drought years of the 1930s and 1950s in parts of the West, but not across the United States as a whole.

Globe
The average temperature for the Northern Hemisphere during summer (June-August) was second warmest on record and second warmest for the month of August. The average global surface temperature for combined land and ocean surfaces during June-August 2003 (based on preliminary data) was 1.0 degree F (0.55 degrees C) above the 1880-2002 long-term mean. August global average temperature was 1.0° F degree (0.58 degrees C) above the long-term mean. The warmest August and boreal summer on record occurred in 1998. Since 1900, global surface temperatures have risen at a rate of 1.0 degree F/century (0.6 degrees C/century), but the rate has increased to approximately three times the century-scale trend since 1976.

Land-surface temperatures for June-August were the third warmest in the historical record. The record warmth that had plagued much of Europe in July continued into early August. The all-time maximum temperature record in the United Kingdom was broken on August 10, with 100.6 degrees F (38.1 degrees C) recorded at Gravesend-Broadness (Kent). It was the warmest summer on record for France.

NOAA Satellites and Information Service is the nation’s primary source of space-based meteorological and climate data. It operates the nation's environmental satellites, which are used for weather forecasting, climate monitoring and other environmental applications such as fire detection, ozone monitoring and sea surface temperature measurements.

The agency also operates three data centers, which house global databases in climatology, oceanography, solid earth geophysics, marine geology and geophysics, solar-terrestrial physics, and paleoclimatology.

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Relevant Web Sites
Climate of 2003 — August in Historical Perspective

NOAA National Climatic Data Center

Media Contact:
John Leslie, NOAA Satellites and Information Service, (301) 457-5005