Climate Division Data

Climate division data is provided on a monthly basis by the National Climatic Data Center [1]. Parameters include precipitation, temperature, and various drought indices.

The Palmer Drought Severity Index attempts to measure the duration and intensity of the long-term drought-inducing circulation patterns. Long-term drought is cumulative, so the intensity of drought during the current month is dependent on the current weather patterns plus the cumulative patterns of previous months. Since weather patterns can change almost literally overnight from a long-term drought pattern to a long-term wet pattern, the PDSI (PDI) can respond fairly rapidly. Note that man-made changes are not considered in this calculation. PDSI index values generally range from -6 to +6, where negative values denote dry spells, and positive values denote wet spells.

The Palmer Hydrological Drought Index is another long-term drought index that takes into account hydrological impacts (e.g., reservoir levels, groundwater levels, etc.), as such impacts take longer to develop, and it takes longer to recover from them. The PHDI responds more slowly to changing conditions than the PDSI (PDI). Note that man-made changes, such as increased irrigation, new reservoirs, and added industrial water use were not included in the calculations for this index. As with PDSI, PHDI values generally range from -6 to +6, where negative values denote dry spells, and positive values denote wet spells.

The Palmer "Z" Index shows how the moisture conditions depart from normal, and can reflect above-normal precipitation events, even during periods of drought. Z index values typically range from -2.75 to 3.5, where negative values indicate dry spells, and positive values indicate wet spells.

The Modified Palmer Drought Severity Index was instituted by the National Weather Service Analysis Center, who modified the PDSI for operational meteorological purposes. The selection for the modified PDSI value for a given month is made internally by the program based on probabilities, in that the modification incorporates a weighted average of the wet and dry index terms using probability as the weighting factor. In general, PMDI and PDSI values will be the same during an established wet or dry spell, but will differ during periods of transition.

The Standardized Precipitation Index is a probability index that considers only precipitation. The SPI is based on the probability of recording a given amount of precipitation, and the probabilities are standardized so that an index of zero indicates the median precipitation amount (half of the historical precipitation amounts are below the median, and half are above the median). The index is negative for drought, and positive for wet conditions. As the dry or wet conditions become more severe, the index becomes more negative or positive. The SPI is computed by NCDC for several time scales, ranging from one month to 24 months, to capture the various scales of both short-term and long-term drought.

You can retrieve or graph climate division data as far back as 1895 by selecting a region of North Carolina, parameters of interest, and a time range over which to pull data.

NC CLIMATE DIVISIONS

     Southern Mountains
     Northern Mountains
     Northern Piedmont
     Central Piedmont
     Southern Piedmont
     Southern Coastal Plain
     Central Coastal Plain
     Northern Coastal Plain

Select a region of North Carolina:
Northern Mountains Southern Mountains Northern Piedmont Central Piedmont Southern Piedmont Northern Coastal Plain Central Coastal Plain Southern Coastal Plain Mountains Piedmont Coastal Plain All of NC


Select parameter(s):
Precipitation
Temperature
Heating Degree Days
Cooling Degree Days
Palmer Drought Severity Index
Palmer Hydrological Drought Index
Palmer Z Index
Modified Palmer Drought Severity Index
1-month Standardized Precipitation Index
2-month Standardized Precipitation Index
3-month Standardized Precipitation Index
6-month Standardized Precipitation Index
9-month Standardized Precipitation Index
12-month Standardized Precipitation Index
24-month Standardized Precipitation Index

MONTHLY TIME SERIES Retrieve monthly data between the chosen start and end dates Select a start date: January February March April May June July August September October November December 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Select an end date: January February March April May June July August September October November December 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957 1956 1955 1954 1953 1952 1951 1950 1949 1948 1947 1946 1945 1944 1943 1942 1941 1940 1939 1938 1937 1936 1935 1934 1933 1932 1931 1930 1929 1928 1927 1926 1925 1924 1923 1922 1921 1920 1919 1918 1917 1916 1915 1914 1913 1912 1911 1910 1909 1908 1907 1906 1905 1904 1903 1902 1901 1900 1899 1898 1897 1896 1895

– OR –

SEASONAL TIME SERIES Retrieve averages/sums calculated over the chosen month(s), for each year between the start and end years Calculate averages/sums from: January February March April May June July August September October November December    to    December November October September August July June May April March February January Select start and end years: 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012    to    2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957 1956 1955 1954 1953 1952 1951 1950 1949 1948 1947 1946 1945 1944 1943 1942 1941 1940 1939 1938 1937 1936 1935 1934 1933 1932 1931 1930 1929 1928 1927 1926 1925 1924 1923 1922 1921 1920 1919 1918 1917 1916 1915 1914 1913 1912 1911 1910 1909 1908 1907 1906 1905 1904 1903 1902 1901 1900 1899 1898 1897 1896 1895

Choose an output format:
(only important if not graphing)
web page Excel spreadsheet comma delimited tab delimited