| Year | Severe to extreme drought | Severe to extreme wetness | Year | Severe to extreme drought | Severe to extreme wetness | Year | Severe to extreme drought | Severe to extreme wetness | ||
| % area | % area | % area | ||||||||
| 1900 | 15.5 | 5.8 | 1934 | 46.4 | 0.4 | 1968 | 3.2 | 8.4 | ||
| 1901 | 18.2 | 4.1 | 1935 | 20.6 | 3.5 | 1969 | 0.5 | 11.0 | ||
| 1902 | 22.5 | 6.8 | 1936 | 22.1 | 2.7 | 1970 | 0.6 | 6.1 | ||
| 1903 | 7.1 | 13.1 | 1937 | 17.0 | 5.0 | 1971 | 5.1 | 9.0 | ||
| 1904 | 13.5 | 9.1 | 1938 | 7.2 | 7.0 | 1972 | 3.5 | 12.9 | ||
| 1905 | 6.7 | 19.3 | 1939 | 15.9 | 3.2 | 1973 | 2.7 | 30.9 | ||
| 1906 | 0.9 | 25.9 | 1940 | 17.7 | 2.3 | 1974 | 4.0 | 15.3 | ||
| 1907 | 0.9 | 29.5 | 1941 | 10.4 | 27.2 | 1975 | 0.5 | 20.8 | ||
| 1908 | 2.2 | 16.2 | 1942 | 3.7 | 28.7 | 1976 | 6.9 | 9.2 | ||
| 1909 | 5.0 | 18.8 | 1943 | 3.5 | 11.5 | 1977 | 22.7 | 4.7 | ||
| 1910 | 14.6 | 7.4 | 1944 | 4.9 | 8.7 | 1978 | 2.8 | 14.0 | ||
| 1911 | 18.6 | 7.3 | 1945 | 2.7 | 18.1 | 1979 | 1.1 | 21.9 | ||
| 1912 | 0.8 | 17.3 | 1946 | 1.9 | 9.4 | 1980 | 5.1 | 11.6 | ||
| 1913 | 3.2 | 15.5 | 1947 | 4.8 | 12.6 | 1981 | 13.1 | 4.5 | ||
| 1914 | 6.6 | 17.8 | 1948 | 5.9 | 10.2 | 1982 | 1.1 | 17.5 | ||
| 1915 | 4.3 | 25.9 | 1949 | 3.6 | 6.6 | 1983 | 0.0 | 36.0 | ||
| 1916 | 1.0 | 29.4 | 1950 | 6.3 | 10.1 | 1984 | 2.2 | 26.3 | ||
| 1917 | 8.7 | 17.8 | 1951 | 11.5 | 14.6 | 1985 | 2.9 | 21.0 | ||
| 1918 | 13.1 | 5.0 | 1952 | 11.0 | 11.0 | 1986 | 4.4 | 15.1 | ||
| 1919 | 4.0 | 13.1 | 1953 | 15.8 | 3.5 | 1987 | 7.8 | 16.5 | ||
| 1920 | 1.7 | 20.9 | 1954 | 36.6 | 2.7 | 1988 | 22.2 | 5.8 | ||
| 1921 | 4.0 | 8.9 | 1955 | 26.0 | 1.7 | 1989 | 18.7 | 6.9 | ||
| 1922 | 4.8 | 5.2 | 1956 | 34.1 | 4.3 | 1990 | 19.0 | 7.2 | ||
| 1923 | 4.7 | 10.9 | 1957 | 13.0 | 11.6 | 1991 | 9.2 | 9.0 | ||
| 1924 | 11.8 | 11.2 | 1958 | 1.6 | 18.4 | 1992 | 10.8 | 18.3 | ||
| 1925 | 18.1 | 2.6 | 1959 | 9.4 | 3.9 | 1993 | 1.2 | 35.1 | ||
| 1926 | 9.4 | 7.0 | 1960 | 9.5 | 6.7 | 1994 | 6.9 | 14.8 | ||
| 1927 | 5.7 | 17.7 | 1961 | 12.0 | 7.1 | 1995 | 1.6 | 24.8 | ||
| 1928 | 5.1 | 15.3 | 1962 | 3.1 | 6.0 | 1996 | 7.9 | 23.2 | ||
| 1929 | 6.9 | 12.9 | 1963 | 16.5 | 2.0 | 1997 | 3.5 | 25.7 | ||
| 1930 | 12.1 | 4.7 | 1964 | 18.3 | 3.0 | 1998 | na | na | ||
| 1931 | 28.9 | 6.1 | 1965 | 6.3 | 14.2 | 1999 | na | na | ||
| 1932 | 8.6 | 8.9 | 1966 | 8.2 | 5.6 | 2000 | 34.0 | 4.0 | ||
| 1933 | 9.9 | 2.4 | 1967 | 6.1 | 6.0 | |||||
Source: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Climatic Data Center, Climate of 2000, September Review (DOC, NOAA, NCDC, Asheville, NC, October 2000), and earlier reports.
Notes: This table presents the average annual values of the percent area experiencing severe to extreme drought and wet conditions based on the Palmer Drought Severity Index (PDSI). PDSI is based on a water balance model that consists of a hydrologic accounting between water supply and demand. The index values range from negative (indicating drought), to zero (near normal conditions), to positive (wet spell). The index has been calculated on a monthly basis for the contiguous United States since 1896.
Last Updated on