Hurrell Station-Based Seasonal NAO Index DJF JFM FMA MAM AMJ MJJ JJA JAS ASO SON OND NDJ 1865 -1.5 -0.9 -0.8 -0.1 -0.4 -0.1 0.9 2.0 0.2 -1.0 -0.9 0.3 1866 1.1 0.5 -0.6 -2.4 -2.2 -1.0 0.2 1.1 0.9 0.5 -0.3 -2.3 1867 -1.2 -3.3 -1.0 -4.0 -1.0 -3.5 0.0 0.8 2.9 -0.6 -0.9 -1.2 1868 2.1 3.7 4.7 4.5 3.9 3.4 2.8 -0.7 1.5 -0.4 0.5 -0.3 1869 2.0 2.1 1.7 -1.0 -2.6 -2.8 -1.7 -0.8 -1.5 0.0 0.0 0.9 1870 -1.4 -2.2 -2.6 -0.3 1.6 1.4 -1.3 -1.3 -0.7 -0.8 -2.4 -1.2 1871 -0.4 1.3 -0.7 -1.3 -3.0 -1.0 -0.1 -0.9 -0.9 -2.9 -0.9 -0.2 1872 0.6 -0.3 -1.3 -0.7 0.3 -0.3 -2.1 -3.3 -0.8 0.5 0.6 0.8 1873 0.2 1.0 -1.0 -1.2 -1.9 0.4 2.6 0.1 1.3 -1.2 0.2 0.4 1874 1.6 1.7 1.8 1.1 0.6 -0.4 0.9 1.7 2.3 1.5 0.7 -0.5 1875 -1.0 -1.3 -1.8 -0.5 1.6 2.7 0.5 -2.2 -1.2 -2.7 -1.9 -1.2 1876 -0.2 0.3 -0.3 0.4 1.7 3.2 3.0 -1.2 -3.0 -5.9 -4.3 -2.6 1877 0.2 1.1 -0.4 -2.7 -3.8 -1.2 -2.2 -4.0 -3.7 0.1 2.6 2.6 1878 1.2 0.2 -1.1 -1.5 -3.0 -1.0 -2.2 -0.9 -1.8 -2.5 -5.4 -4.7 1879 -2.4 0.6 1.2 1.5 0.1 0.1 -1.3 1.3 1.0 -1.6 -2.9 -2.9 1880 -0.4 0.4 1.4 0.8 0.5 -2.0 -1.9 -2.4 -3.9 -2.6 -2.9 -4.4 1881 -4.7 -4.7 -2.7 -2.4 -0.3 2.0 1.0 -0.9 -2.0 -0.6 1.9 2.7 1882 2.1 2.5 2.0 1.5 -1.5 0.0 1.2 2.1 1.2 2.0 0.2 0.5 1883 1.2 0.7 0.8 -0.6 0.5 -1.5 -1.8 -0.9 1.8 2.5 2.5 1.6 1884 1.1 1.4 0.4 0.0 -0.8 -0.6 -0.3 0.0 2.0 0.7 1.2 0.3 1885 -0.4 -0.7 -0.2 0.7 0.8 0.1 -1.3 -1.0 -1.2 -0.2 -1.5 -1.0 1886 -0.5 -0.4 -1.1 -1.8 -1.2 0.0 2.3 1.1 1.1 1.0 1.0 1.6 1887 1.4 0.6 -1.7 -2.9 -2.9 -0.9 -2.4 -1.7 -3.5 -3.1 -3.6 -2.8 1888 -3.0 -2.4 -2.2 -2.1 -2.1 -2.6 -2.0 -2.7 -3.6 -1.6 0.6 2.5 1889 1.5 0.6 0.8 1.1 2.4 -0.1 0.3 -1.5 0.6 1.2 3.1 3.8 1890 2.3 1.8 1.4 2.2 1.7 1.1 2.0 1.9 1.1 2.5 0.9 1.0 1891 0.2 0.0 -0.7 -2.0 -3.5 -3.8 -3.3 0.0 1.7 1.4 1.5 1.2 1892 0.0 -1.4 -2.2 -2.3 -2.4 -2.3 -1.1 1.2 -1.1 -0.4 -1.8 -1.7 1893 -1.3 -0.9 0.2 -0.9 -2.1 -2.1 -2.8 -0.4 -0.1 -0.6 0.3 0.5 1894 3.1 2.8 3.7 1.8 2.1 1.5 2.2 -1.8 -3.9 -2.1 0.1 0.2 1895 -3.5 -3.2 -3.0 0.6 -0.4 0.2 -0.4 0.0 -2.0 -2.1 -1.8 -1.1 1896 -0.2 1.2 3.0 3.7 2.1 1.4 0.7 1.0 -1.7 -2.1 -0.5 -0.4 1897 0.6 0.3 2.7 2.6 1.2 -1.7 -1.2 0.8 -0.5 -1.2 -0.9 0.8 1898 1.6 1.1 1.3 0.3 0.2 -2.1 -0.9 -0.5 -0.5 -0.3 0.4 -0.2 1899 -1.5 -2.5 -2.4 -2.3 -0.2 0.8 0.5 0.5 -1.7 -0.3 -1.1 1.0 1900 -1.2 -1.7 -2.9 -0.8 0.6 -0.4 -0.6 1.2 1.1 2.4 1.7 1.6 1901 -1.1 -1.9 -1.8 -0.5 0.7 0.4 2.0 1.8 2.4 0.1 -0.3 -1.2 1902 -1.8 -1.4 -2.2 -0.1 -2.8 -2.8 -4.2 -3.2 -1.4 -0.7 0.5 0.3 1903 1.3 2.8 3.1 3.1 -1.2 -1.4 -1.9 -0.2 -0.6 -0.2 0.3 1.8 1904 1.7 1.7 2.5 2.9 2.9 -0.5 -2.0 -0.9 -0.1 0.2 -0.9 -0.6 1905 0.5 1.7 1.2 0.9 -0.7 0.8 0.2 1.3 -0.5 0.1 -0.6 1.4 1906 2.0 1.8 2.0 -0.2 -0.6 -1.4 -0.5 1.1 0.8 1.4 1.5 1.3 1907 2.0 2.8 3.5 2.1 -0.1 -2.5 -1.0 -1.4 -0.1 1.4 1.4 1.8 1908 2.0 2.7 2.3 1.7 0.4 1.1 0.2 -0.2 -0.6 -0.3 0.7 1.9 1909 1.5 -0.2 -0.9 -2.0 -1.3 -0.4 2.1 1.6 1.6 -0.7 -1.4 -0.8 1910 2.0 3.7 2.8 1.8 0.9 1.5 -0.8 -1.7 -1.7 -2.4 -1.7 -0.6 1911 0.7 0.9 0.4 1.1 1.3 1.2 -1.3 -1.3 -0.9 -0.1 0.4 -0.1 1912 -1.6 -1.0 -0.1 2.3 1.2 0.0 -1.1 -2.5 -0.7 0.6 2.3 1.7 1913 1.3 1.9 2.9 4.2 3.4 1.3 0.9 -1.0 -1.7 0.6 1.2 1.4 1914 0.6 1.2 2.2 2.8 3.6 2.7 1.4 -0.1 -0.1 -0.3 0.6 1.2 1915 1.6 -0.6 0.0 -1.9 -0.5 -3.0 -2.7 -2.5 -1.1 -2.0 -2.4 -1.4 1916 1.1 0.7 0.0 -1.9 -0.4 -1.1 -1.7 -1.3 0.4 0.8 -1.2 -3.4 1917 -3.6 -2.1 -2.0 -2.8 -3.1 -2.3 -0.8 0.0 1.9 3.1 0.7 -2.9 1918 -1.8 -0.6 1.9 0.5 0.7 -0.3 0.1 -0.3 2.2 1.8 1.4 0.5 1919 -1.3 -1.6 -1.6 0.0 1.9 0.7 1.6 0.3 0.0 -1.4 0.0 1.9 1920 2.9 3.4 2.0 2.6 -0.2 2.6 0.8 1.7 0.2 1.9 0.0 1.0 1921 0.2 2.4 1.7 3.2 0.7 0.7 -0.7 -0.2 -0.5 -1.2 0.7 1.5 1922 3.0 2.0 2.0 0.9 2.2 3.3 3.3 2.5 -1.1 -1.7 -1.3 1.3 1923 1.7 1.2 0.8 0.0 0.3 1.0 1.7 2.3 1.9 1.8 1.4 0.9 1924 0.3 -1.8 -3.4 -3.9 -1.7 0.5 1.6 2.4 1.8 1.4 2.3 2.3 1925 3.0 1.1 1.5 1.1 3.0 2.9 2.4 1.7 -0.7 -2.2 -4.0 -2.7 1926 -1.5 0.5 0.7 0.0 -1.0 -1.4 -0.2 0.2 -2.1 -0.6 -0.7 1.7 1927 0.8 2.0 1.6 1.0 -0.7 -1.6 -0.1 -0.1 -2.1 -1.6 -3.1 0.4 1928 1.1 2.0 0.8 -1.6 -2.6 -3.1 -1.9 -0.9 0.2 1.9 2.1 -1.5 1929 -2.2 -3.0 -2.1 -1.6 -1.1 0.9 -0.4 0.8 2.0 3.0 3.3 3.0 1930 1.8 0.1 -0.8 0.1 2.5 2.9 1.4 -1.9 -1.0 -0.2 2.0 1.5 1931 2.0 -0.7 -0.3 -2.3 -0.5 -0.6 -1.1 -0.9 -2.1 0.4 0.9 1.8 1932 -1.4 -2.0 -2.7 -1.2 -0.9 -0.9 0.8 1.7 1.9 1.6 1.1 1.2 1933 -0.3 0.0 -1.7 -0.3 -0.1 2.3 3.1 1.6 -0.9 -1.2 -1.1 0.9 1934 1.0 2.2 0.9 1.7 -0.9 0.8 0.2 2.7 2.6 1.2 -0.5 -0.8 1935 0.7 1.2 0.8 -1.6 -1.9 1.0 3.2 2.9 3.3 3.5 1.5 -2.0 1936 -3.9 -3.5 -2.6 -0.9 0.1 1.2 1.8 0.1 1.3 1.8 2.8 1.9 1937 0.9 -0.5 -0.7 -0.3 1.3 0.8 0.4 1.6 0.8 -1.9 -2.5 -0.6 1938 0.2 1.8 0.0 1.2 -0.2 2.3 2.3 2.5 3.8 4.4 3.2 0.0 1939 0.5 0.4 1.7 0.4 -0.3 -0.3 0.1 -2.1 -1.9 -1.0 -0.5 -1.8 1940 -3.4 -3.2 -2.5 -1.4 0.4 0.9 1.5 0.5 0.2 1.0 0.6 -1.2 1941 -2.2 -2.5 -1.7 -1.4 -0.8 1.1 1.0 0.2 -1.3 -1.3 -0.1 1.4 1942 -0.3 -1.6 -3.1 -1.7 -1.3 -0.5 0.5 2.8 2.4 0.5 -0.2 -1.0 1943 1.3 1.5 3.5 2.5 3.0 0.9 -0.2 0.9 1.2 2.7 1.8 2.0 1944 1.0 -0.4 -1.3 -1.3 -0.1 -1.0 -0.7 0.2 2.5 2.0 1.8 -0.5 1945 0.8 0.5 1.2 -0.7 -1.6 0.2 1.0 1.1 -0.5 -3.0 -3.6 -1.5 1946 -0.2 0.7 1.1 0.7 2.0 0.9 3.5 2.8 -0.4 -1.6 -0.8 0.3 1947 -1.8 -3.7 -3.1 -0.5 2.2 0.2 0.2 1.6 0.9 -0.3 -2.3 -1.5 1948 -0.8 1.1 1.5 2.2 0.8 -0.7 -0.6 -0.3 1.0 -0.2 -0.5 -0.5 1949 1.3 1.4 2.1 1.1 0.8 -1.4 -1.9 -1.5 -0.8 0.8 1.1 1.0 1950 1.0 0.8 1.6 0.0 -0.1 -1.4 0.7 2.5 2.8 1.6 -0.3 -0.1 1951 0.9 0.3 -0.9 -3.1 -3.5 -2.7 -0.5 1.1 2.0 0.9 2.0 2.5 1952 1.5 -0.6 -1.2 -1.3 0.3 -1.0 0.0 -1.1 -1.3 -2.2 -1.5 -2.0 1953 -0.7 0.0 -0.3 -1.4 -1.8 0.9 2.8 2.8 2.6 3.0 2.4 1.7 1954 1.5 1.3 1.8 0.3 0.4 1.0 2.0 2.7 1.8 3.0 2.5 0.5 1955 -1.7 -3.4 -2.6 -1.5 0.4 0.5 1.2 3.5 1.4 -1.4 -2.7 -2.3 1956 -2.0 -1.3 -1.7 1.6 2.0 3.1 -0.5 -1.4 -0.2 1.4 2.2 2.8 1957 1.2 -0.4 -1.3 -0.7 -0.5 -2.3 -2.2 -1.6 1.1 -0.7 0.9 -0.6 1958 -1.1 -2.8 -2.4 -1.4 -0.2 -2.4 -2.4 -2.0 0.3 1.7 1.1 -1.6 1959 -1.2 0.0 2.3 1.5 1.0 1.3 1.5 0.6 0.9 1.6 2.4 0.3 1960 -2.2 -3.2 -2.1 0.2 1.3 1.1 -0.6 0.0 -2.6 -0.8 0.2 1.9 1961 2.0 1.1 0.3 -0.9 0.0 1.2 2.7 2.1 2.8 1.8 -1.9 -1.0 1962 -0.2 -0.4 -1.6 -3.1 0.0 -1.4 -0.9 -1.0 0.1 -0.5 -0.9 -3.9 1963 -4.0 -2.9 -0.7 2.3 1.3 1.3 -1.9 0.4 2.5 1.2 -1.1 -2.8 1964 -2.8 -2.2 -1.3 0.3 1.6 1.7 -0.8 -1.2 -0.8 0.7 0.8 0.1 1965 -2.2 -2.7 -1.9 0.4 2.3 -0.3 0.5 -0.3 -0.3 -1.7 -0.9 -2.7 1966 -3.1 -3.0 -1.9 0.7 0.9 2.2 -0.6 -1.9 -4.0 -2.0 -0.1 0.3 1967 0.8 1.0 2.5 1.9 1.2 0.7 1.1 0.0 1.5 2.0 0.9 0.3 1968 -1.1 0.1 -0.9 0.0 -1.6 -2.0 -2.1 -2.8 -3.0 -3.6 -3.1 -3.6 1969 -4.3 -4.7 -3.0 -1.7 0.4 -0.2 0.3 1.4 1.0 0.7 0.7 -1.4 1970 -0.3 -1.5 0.4 0.4 2.0 1.4 -0.1 -0.2 -0.5 -0.2 -1.1 -1.5 1971 -0.8 0.0 0.1 0.2 -0.9 -0.4 -0.9 -0.9 -0.3 -0.2 0.9 1.2 1972 0.9 1.1 1.5 2.6 3.9 3.1 1.6 -2.1 -2.4 -1.3 1.0 1.7 1973 2.4 1.9 0.8 -1.4 -1.8 0.7 1.7 0.4 -0.6 -1.6 -1.1 0.8 1974 1.9 2.0 0.8 0.0 -0.8 -0.2 -0.1 1.0 0.3 0.9 1.4 2.1 1975 1.2 0.2 -0.5 -0.6 -0.8 -1.3 -0.9 0.8 0.1 1.1 -0.1 0.7 1976 0.8 2.1 2.2 3.0 2.1 0.8 -2.1 -5.3 -2.2 -0.3 -0.2 -1.8 1977 -2.7 -1.7 -0.7 -0.2 -0.5 -0.9 -1.0 -0.6 -0.1 -0.4 -0.9 -0.1 1978 -1.6 0.5 -1.1 1.8 0.1 0.6 -1.4 -1.9 -0.8 1.8 -0.5 -2.0 1979 -3.4 -1.3 -0.5 0.1 -0.8 0.5 0.6 0.5 0.4 1.2 1.6 0.2 1980 0.0 -0.6 0.2 -1.0 -0.8 -1.4 -1.1 -0.8 -1.0 -2.0 -1.1 0.2 1981 1.9 0.6 -0.3 -1.4 -1.6 -0.3 -0.1 0.8 0.2 -0.5 -1.2 -2.0 1982 -0.5 1.4 2.2 1.9 -1.4 -1.3 -0.8 1.2 2.0 2.4 3.2 4.0 1983 1.9 1.7 -0.1 0.7 -0.7 -0.1 0.9 -0.6 1.0 -2.1 -0.8 0.6 1984 2.9 1.7 -0.5 -1.3 0.2 0.5 -0.3 -0.3 1.3 1.2 1.6 -0.8 1985 -1.7 -2.0 -0.6 0.2 -1.3 -1.4 -0.3 -0.3 -0.6 -2.7 -2.1 -0.1 1986 -0.7 1.5 0.4 3.9 1.7 2.1 -1.2 -3.5 -0.6 3.0 4.4 0.3 1987 -1.5 -2.2 -0.3 -0.5 -1.2 -1.8 -2.3 -1.6 -0.8 0.4 -0.9 -0.4 1988 -0.2 1.1 -0.2 -0.7 -1.7 0.3 1.4 1.5 -0.2 -2.2 -1.6 0.8 1989 3.4 4.5 4.2 2.9 0.2 -0.7 0.3 0.8 1.4 -0.6 -2.3 -0.5 1990 1.9 4.4 4.5 2.5 1.6 -0.7 1.0 0.1 0.3 -0.8 0.3 0.5 1991 1.2 0.6 0.7 0.8 0.9 -0.4 -0.3 -0.1 0.2 0.7 0.8 0.2 1992 0.7 1.5 3.2 2.5 1.3 0.1 1.0 0.9 -0.1 0.6 1.3 2.9 1993 1.9 1.8 1.4 0.1 -1.1 -2.5 -0.4 -1.9 -1.9 0.1 2.5 3.7 1994 2.0 2.9 2.6 3.6 1.5 1.3 1.2 -0.2 -1.3 -0.7 0.5 1.8 1995 2.8 2.9 1.8 0.1 -2.7 -2.1 -2.1 -0.7 -0.3 -2.0 -3.9 -4.4 1996 -2.1 -1.6 -1.3 -3.2 -1.4 -0.2 1.2 0.5 1.1 1.5 -0.8 -2.8 1997 -0.8 1.3 2.4 -0.8 -3.7 -2.4 -0.9 0.4 -1.8 -1.9 -1.4 -0.7 1998 -0.2 0.2 1.0 0.6 -0.1 -0.6 0.3 -0.4 0.3 0.4 1.8 2.0 1999 2.7 2.0 1.6 0.4 0.9 0.2 -1.3 -1.3 -0.2 1.2 1.6 1.4 2000 2.6 1.9 1.3 -0.4 -1.2 -0.6 -1.4 -0.9 3.3 2.8 0.8 -1.2 2001 -1.3 -1.1 -0.6 -0.8 -0.4 -1.5 -0.6 -1.2 -0.5 0.4 -1.2 -1.1 2002 -0.5 1.6 2.5 2.5 3.5 2.9 2.1 -1.6 -3.2 -2.3 -1.7 -0.4 2003 -0.2 1.1 0.3 -0.3 -1.1 0.5 -1.0 -1.1 -1.7 0.1 -0.3 0.2 2004 -1.1 0.0 0.6 2.3 0.9 -0.4 -1.8 0.3 -0.9 -0.4 0.5 1.9 2005 1.4 -1.3 -2.0 -2.8 -1.4 -1.9 -0.1 1.4 0.3 0.1 -0.7 0.6 2006 -0.2 -0.7 -1.1 -1.1 0.2 -0.4 -0.5 -0.6 -2.1 -0.8 0.7 2.3 2007 1.4 1.9 1.6 3.4 -0.2 -0.5 -2.5 -0.6 0.5 -0.3 0.3 0.8 2008 1.4 1.7 0.1 -1.1 -3.2 -1.4 0.9 1.1 3.0 3.0 2.3 1.9 2009 1.0 1.6 2.0 3.8 1.6 -1.2 -1.9 1.0 0.0 0.7 -2.5 -2.5 2010 -5.2 -3.7 -4.2 -2.8 -2.4 0.1 -0.3 -0.2 -1.4 -1.7 -4.4 -4.3 2011 -2.1 0.6 2.2 2.1 1.9 0.7 -1.1 0.2 1.2 2.2 3.3 3.4 2012 3.2 1.9 1.5 -0.4 -2.6 -3.7 -2.8 -1.2 -2.9 -0.9 -0.8 1.1 2013 0.4 -1.6 -2.5 -2.2 2.2 2.3 1.8 0.6 0.3 0.5 2.0 3.4 2014 3.6 3.3 2.5 1.9 -0.4 0.1 -1.2 -1.4 -1.2 -0.5 2.0 3.9 2015 4.6 4.5 3.3 3.1 0.7 -0.2 -0.9 -1.4 -0.8 0.8 1.6 1.6 2016 1.8 2.0 1.7 -0.2 -1.7 -0.5 0.1 2.0 0.6 1.2 0.4 0.7 2017 0.9 1.2 1.2 -0.3 -1.4 0.1 1.8 2.4 1.7 0.6 0.1 1.4 2018 2.2 1.3 0.5 1.5 2.9 3.1 1.8 2.1 1.8 0.7 0.4 0.1 2019 0.2 1.3 1.6 1.2 -2.2 -2.8 -2.0 -0.1 -0.6 0.0 0.1 1.9 2020 3.4 3.8 2.6 0.2 -2.1 -0.9 -0.5 0.7 0.8 2.1 1.5 0.2 2021 -0.7 -0.4 -0.9 -1.0 -1.8 0.3 -0.6 -0.8 0.0 0.9 -0.1 0.1 2022 1.7 2.4 1.8 0.1 0.0 1.7 1.1 -0.6 -999. -999. -999. -999.