National Climatic Data Center, 15 August 2002

• about 49 percent of the contiguous U.S. fell in the moderate to extreme drought categories (based on the Palmer Drought Index) at the end of July;
• severe drought affected about 37 percent of the contiguous United States as of the end of July 2002, which is about the same as the 36 percent coverage at the end of June;
• the coverage of the current (November 1999-present) national-scale drought first peaked in August 2000 at about 36% of the contiguous U.S., which was as extensive as the major droughts of the last 40 years, but not as large as the "dust bowl" droughts of the 1930s and 1950s;
• the total drought area decreased to about 10 percent by November 2000, but has shown a general increasing trend for much of the period since then, reaching in June 2002 the peak it had first reached in August 2000 (see graph below left);
• on a broad scale, the last two decades were characterized by unusual wetness with short periods of extensive droughts, whereas the 1930s and 1950s were characterized by prolonged periods of extensive droughts with little wetness (see graph below right);
• although various parts of the U.S. have experienced unusually wet conditions during the last 33 months, little change occurred in the aggregate national wetness picture during much of this period;
• the percentage of the nation severely wet has remained below about eleven percent during this period, reaching about 3 percent by the end of July 2002 (see graph below left);
• a file containing the national monthly percent area severely dry and wet from 1900 to present is available;
• historical temperature, precipitation, and Palmer drought data from 1895 to present for climate divisions, states, and regions in the contiguous U.S. are available at the Climate Division: Temperature-Precipitation-Drought Data page in files having names that start with "drd964x" and ending with "txt" (without the quotes).