MONTHLY NAO INDEX BASED ON STANDARDIZED ANOMALIES JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1874 1.5 0.5 0.5 1.9 -1.5 0.2 0.5 0.6 1.5 1.7 -0.6 -0.4 1875 -0.8 -1.3 -1.4 -2.0 1.8 2.8 -1.3 -1.9 -1.6 -0.2 -3.3 -0.4 1876 0.7 -1.0 0.1 -0.9 0.6 3.1 1.7 0.0 -4.2 -2.9 -5.2 -2.3 1877 0.8 0.8 -0.3 -3.9 -3.1 -0.8 1.3 -5.8 -3.5 -0.6 1.8 1.9 1878 0.5 -0.4 -0.2 -3.4 -1.4 -1.7 0.7 -3.7 1.0 -2.0 -3.4 -5.4 1879 -1.1 0.4 0.6 -0.4 1.2 -2.0 -1.1 -1.1 3.0 -0.5 -4.4 -1.3 1880 -1.4 0.7 -1.0 1.3 -0.9 -0.6 -4.2 -1.0 -1.5 -7.6 0.6 -2.2 1881 -5.4 -1.5 -3.2 -2.5 0.3 0.8 1.5 -1.2 -3.0 -1.6 0.9 2.2 1882 0.9 0.2 3.1 -2.0 -1.8 -0.6 1.3 0.3 1.4 -0.6 1.4 -1.7 1883 0.5 1.9 -2.8 0.9 1.1 -2.9 -3.5 0.9 -1.3 2.2 1.5 0.5 1884 0.6 0.3 0.5 -2.6 -0.1 0.3 -4.1 0.0 1.4 1.3 -1.7 1.6 1885 -0.4 -2.1 0.5 0.8 -2.1 1.1 -0.2 -5.1 1.6 0.0 -1.7 -1.4 1886 0.3 -0.5 -1.6 -1.6 -1.5 0.2 0.4 2.5 -1.3 0.2 1.4 -0.4 1887 1.6 0.6 -2.6 -3.7 0.4 -2.7 -0.6 -2.6 -0.7 -4.2 -1.6 -2.5 1888 -1.4 -1.8 -1.9 -1.1 -1.6 -2.3 -2.5 -0.8 -3.5 -3.8 1.8 1.2 1889 1.1 0.1 -0.6 1.9 -0.2 1.5 -3.6 1.6 -1.5 0.9 1.5 2.5 1890 2.3 -0.9 1.5 1.5 -1.0 1.5 1.4 0.5 1.1 0.0 2.4 -1.2 1891 0.1 0.1 -1.5 -2.2 -1.0 -4.7 -2.9 0.0 1.4 0.3 -0.3 1.5 1892 0.5 -2.1 -2.0 -1.1 -2.4 -2.1 -0.3 -0.8 2.1 -3.8 0.3 -1.5 1893 -2.0 0.3 -1.0 -0.4 -1.8 -3.5 -0.4 -3.2 0.5 -0.5 -2.6 2.1 1894 0.6 2.8 1.2 1.5 -1.2 2.1 0.3 -0.3 -4.8 -4.3 1.8 0.6 1895 -1.5 -5.0 0.4 -1.2 0.0 -1.1 -0.9 -1.3 -0.7 -3.7 -0.9 -0.5 1896 -0.7 0.5 2.3 2.4 0.7 -1.4 1.7 -0.4 0.5 -2.8 -1.3 1.7 1897 -1.2 1.0 0.4 3.6 -0.1 -3.1 -1.6 0.6 0.8 -3.3 -0.9 0.6 1898 1.4 1.1 -0.8 2.2 -1.2 -2.2 -2.2 0.6 -1.5 -1.9 0.9 0.6 1899 -0.9 -1.9 -2.7 -0.5 -1.7 1.0 1.5 -3.0 1.2 -3.3 0.4 -0.7 1900 1.8 -3.1 -2.3 0.8 0.3 -1.3 -1.7 -0.6 2.0 -0.8 1.8 1.2 1901 0.2 -2.8 -1.1 1.1 -1.9 1.4 0.8 0.6 0.4 2.0 -2.7 0.3 1902 -0.1 -2.9 0.2 -2.5 0.7 -4.8 -3.3 -2.1 -2.9 0.0 -0.7 0.6 1903 0.3 1.5 3.1 -0.3 0.9 -4.2 -1.2 0.3 -1.0 -1.5 0.6 0.5 1904 2.0 0.6 0.1 4.3 0.1 -1.2 -2.1 -2.2 0.6 -0.5 -0.6 -1.0 1905 0.7 1.4 1.1 -1.9 1.1 -1.5 -0.2 0.0 0.8 -2.6 0.5 -0.1 1906 1.9 1.6 -0.7 2.6 -3.2 -2.2 2.3 -2.7 0.4 0.9 -0.1 1.4 1907 0.9 1.5 2.9 1.4 -3.2 0.2 -3.8 -0.9 -0.7 -0.1 1.5 0.5 1908 1.1 2.0 2.0 -1.7 0.5 0.8 -1.3 -0.9 -0.4 -2.3 -0.2 1.5 1909 1.5 -0.3 -2.3 -0.1 -2.6 -0.9 2.8 1.8 -2.2 2.0 -2.1 -2.0 1910 2.0 3.0 1.3 -1.1 2.2 0.0 -1.6 -1.8 -1.7 -1.5 -2.2 -0.2 1911 0.9 0.6 0.0 -1.1 2.5 -0.5 -2.6 -1.3 -0.3 -0.9 0.1 0.9 1912 -0.9 -2.6 1.3 0.9 0.1 -0.3 -1.4 -1.8 -3.1 1.0 1.0 1.9 1913 0.5 -0.1 2.5 2.8 1.0 1.6 -1.6 0.8 -1.8 -2.7 3.6 0.6 1914 -0.1 1.3 1.2 1.6 2.8 2.6 -1.1 0.2 -0.1 -1.0 0.0 1.2 1915 0.8 0.7 -3.4 3.5 -2.6 -3.1 -0.1 -2.7 -2.7 1.0 -3.0 -2.3 1916 2.1 2.0 -3.1 1.2 -0.6 -2.0 -0.1 -2.0 -1.1 2.2 -0.5 -2.8 1917 -1.7 -1.0 -0.6 -2.6 -2.8 0.7 -2.1 -0.5 1.9 2.2 2.0 -1.2 1918 -3.5 2.3 0.5 -0.3 -0.1 1.4 -4.3 0.6 0.5 1.8 0.1 0.8 1919 1.0 -2.8 -0.4 0.2 -1.3 3.9 -0.6 0.0 0.1 -2.5 -1.8 2.2 1920 2.5 1.2 3.5 -1.4 2.1 -0.2 3.2 -1.0 1.1 -0.9 1.8 -1.6 1921 1.6 0.3 3.0 -0.4 2.9 -0.5 -1.4 0.7 -0.4 -1.8 -1.0 2.7 1922 0.8 2.3 0.4 -0.1 1.3 3.0 1.6 1.2 1.6 -4.7 -0.4 2.0 1923 1.7 0.6 -0.5 0.2 -0.6 0.7 2.4 -0.3 1.8 1.0 0.3 1.3 1924 0.6 -0.6 -4.0 -2.4 -0.4 -0.1 1.3 1.4 1.0 0.5 0.4 2.8 1925 1.3 1.9 -1.2 2.2 1.2 0.8 2.5 0.7 -0.3 -2.3 -1.8 -3.5 1926 0.5 0.3 -0.2 0.8 -1.7 -2.3 0.1 0.2 -1.6 -3.2 2.2 -0.6 1927 1.9 0.1 1.5 1.1 -2.5 -0.5 -0.8 -0.5 -0.2 -4.2 0.3 -3.4 1928 3.0 1.5 -1.5 0.8 -3.1 -3.6 0.5 -2.1 -1.5 2.1 1.6 0.7 1929 -3.6 -0.5 -1.7 -3.3 1.8 -1.1 -0.6 -0.1 1.1 2.0 1.9 2.7 1930 1.6 -0.3 -1.2 -0.1 2.1 2.6 -1.2 -0.7 -3.4 0.3 0.9 2.1 1931 0.2 1.9 -4.2 1.3 -1.0 -2.6 1.6 -2.1 -2.0 -1.6 2.1 0.1 1932 1.3 -3.4 -1.6 1.1 -1.6 -1.6 1.2 1.0 0.2 2.0 0.4 0.4 1933 1.8 -2.0 0.3 -2.1 -0.2 2.3 2.1 1.3 -0.8 -2.7 0.1 -0.6 1934 1.8 0.5 2.0 -2.3 2.4 -2.5 0.3 1.8 2.1 1.0 -0.7 -0.8 1935 0.2 2.1 -0.4 -2.3 -1.7 0.3 3.7 1.7 -0.2 3.9 1.6 -1.3 1936 -2.3 -2.6 -1.4 -1.3 0.6 0.4 0.5 1.8 -2.9 2.5 2.2 1.6 1937 0.9 0.0 -2.4 1.0 1.1 -0.9 -0.7 0.5 1.2 -0.9 -3.3 -0.9 1938 2.2 -0.9 2.2 -2.0 0.8 1.4 1.9 1.1 1.6 3.8 2.3 0.9 1939 -1.6 2.1 0.3 -0.6 0.1 -0.5 -1.1 0.8 -4.5 -1.0 1.3 -1.5 1940 -2.1 -2.3 -1.8 -0.7 -0.5 1.7 0.2 0.5 0.1 -0.8 1.5 0.0 1941 -2.5 -1.0 -1.2 -2.2 0.3 0.1 1.3 -0.2 -1.7 -1.4 -0.6 0.9 1942 1.5 -2.7 -2.6 -0.8 -0.5 -2.2 1.4 1.5 2.1 0.8 -1.7 0.4 1943 -0.6 2.5 0.3 3.8 0.3 0.7 0.1 -1.9 2.7 0.1 1.6 1.1 1944 1.2 -0.2 -2.1 -1.0 0.4 -0.7 -3.9 1.5 1.0 2.1 0.3 1.2 1945 -1.7 2.3 0.4 -2.5 -0.5 0.3 0.0 0.9 0.1 -2.5 -3.4 -1.8 1946 1.5 -0.1 -0.2 3.4 -2.4 2.8 2.1 1.5 1.4 -3.6 -1.0 1.5 1947 0.0 -4.1 -3.1 3.7 -0.7 -0.5 0.2 -0.9 2.3 -0.5 -1.9 -1.8 1948 0.7 -0.6 1.6 1.9 -0.6 -0.8 -1.4 -0.4 0.0 1.4 -2.0 -0.3 1949 1.3 1.8 -0.4 2.8 -0.1 -2.2 -1.4 -1.5 -1.1 -0.3 1.4 0.6 1950 0.0 1.3 -0.3 2.2 -2.4 -0.7 -1.1 0.8 3.1 0.8 -0.7 -0.8 1951 1.0 1.2 -2.4 -2.1 -2.0 -3.6 -0.7 1.7 -0.3 1.0 -0.4 2.4 1952 2.0 -1.1 -2.7 2.5 -2.2 -0.4 0.5 -0.9 -1.8 -1.0 -2.0 -0.6 1953 -0.8 0.5 0.2 -2.6 -1.4 1.3 1.7 1.5 1.1 1.1 1.8 1.0 1954 0.4 1.3 0.3 0.6 -1.8 1.3 3.3 -0.4 2.6 0.6 1.7 1.8 1955 -1.5 -2.2 -2.9 0.5 0.1 -0.4 1.2 0.7 3.6 -1.7 -3.4 -0.5 1956 -0.4 -2.1 0.2 -1.5 4.7 1.0 -1.1 -1.2 -1.0 0.6 1.8 1.7 1957 2.0 -0.9 -2.1 0.9 0.0 -3.4 -2.4 0.6 -2.0 2.1 -2.0 1.5 1958 -0.1 -2.2 -3.1 1.7 -0.6 -2.2 -2.7 -0.6 -1.7 1.5 1.4 -0.8 1959 -2.5 1.3 1.1 0.7 -0.7 1.3 1.5 -0.6 -0.8 0.9 1.0 1.9 1960 -1.7 -3.2 -1.3 1.6 -0.5 0.5 1.7 -3.7 1.0 -3.6 0.1 2.1 1961 0.8 0.7 0.0 -1.3 -1.0 3.8 0.6 1.5 2.2 1.9 -0.2 -3.9 1962 2.0 0.8 -4.5 0.3 0.0 -0.4 -2.4 1.1 -0.6 -0.2 -0.5 -1.2 1963 -4.5 -1.3 0.4 -1.0 5.1 -1.9 -2.0 0.6 2.7 1.7 -1.3 -2.4 1964 -1.2 -1.6 -1.8 1.6 1.5 -0.4 2.2 -2.4 -0.8 1.5 0.3 0.1 1965 -0.2 -3.6 -1.5 3.5 -0.7 1.1 -0.6 1.0 0.1 -1.0 -2.0 0.5 1966 -3.1 -2.7 0.2 -1.3 2.2 0.8 1.4 -2.7 -1.0 -3.7 0.9 1.9 1967 -1.4 1.3 2.1 0.9 -0.5 2.3 -0.1 0.2 0.4 2.2 1.0 -0.8 1968 0.5 -1.7 1.4 -2.1 -0.6 0.4 -3.4 -0.6 -0.8 -3.9 -2.1 -1.3 1969 -2.7 -3.2 -3.1 1.7 -1.1 0.1 1.9 -0.6 2.4 0.2 -0.3 1.2 1970 -2.3 0.9 -1.4 1.3 1.9 1.1 0.2 -0.3 0.6 -0.5 0.1 -1.4 1971 -0.8 1.0 0.1 -1.8 2.5 -1.5 -1.5 2.5 -1.7 -0.5 1.5 0.8 1972 0.6 0.4 0.9 1.7 2.7 3.8 -0.3 0.5 -2.9 -1.6 1.6 1.7 1973 0.6 2.3 0.8 -3.1 -0.5 2.5 1.2 1.1 0.1 -1.1 -1.3 0.2 1974 2.3 1.0 -0.1 -0.4 -0.2 -0.7 2.0 0.3 1.7 0.2 0.8 1.9 1975 1.4 -0.8 -0.5 0.5 -0.6 -0.8 0.2 -0.1 2.6 -1.1 1.3 -0.2 1976 0.8 1.1 1.9 0.8 2.6 0.8 -2.5 -2.3 -4.6 1.4 1.2 -2.4 1977 -1.4 -1.2 -0.8 1.0 -0.2 -1.2 0.8 -0.2 -0.6 0.7 -0.5 -1.4 1978 1.4 -3.3 2.6 -2.2 1.4 1.6 -2.1 -1.8 0.5 -0.3 2.6 -3.1 1979 -2.1 -1.2 1.1 -1.4 0.0 0.7 0.8 0.3 0.6 -0.2 1.5 1.5 1980 -1.5 0.2 -0.3 0.0 -1.9 1.8 -1.4 -2.0 1.7 -1.9 -2.8 1.4 1981 1.1 1.0 -1.9 -1.0 -0.2 -1.6 2.0 0.7 -0.5 0.6 -1.0 -1.8 1982 -1.2 1.3 2.2 -0.2 0.7 -3.4 -0.2 2.5 0.8 1.0 2.2 2.4 1983 2.8 -1.1 1.8 -1.2 -0.6 -0.6 0.4 2.0 -2.0 2.1 -3.7 0.2 1984 3.3 1.5 -2.2 -0.8 1.6 0.7 -1.3 1.0 0.6 1.2 0.1 1.5 1985 -2.5 -1.8 0.4 0.0 -0.8 -1.2 0.7 0.7 -1.8 0.2 -2.7 -1.5 1986 2.2 -2.8 3.6 -0.1 1.8 0.9 1.1 -3.2 -3.0 3.9 3.2 1.7 1987 -2.9 -0.9 -0.4 1.1 -1.4 -1.1 0.4 -3.0 -0.6 0.7 0.2 -2.4 1988 0.9 0.3 -0.4 -2.8 -0.8 1.0 0.6 1.2 1.0 -1.8 -2.3 0.6 1989 2.5 3.0 2.8 0.9 0.3 -1.2 0.4 2.2 0.1 0.7 -1.3 -3.1 1990 3.0 2.8 2.2 3.9 -1.6 1.0 0.0 0.9 -0.1 0.1 -1.7 1.6 1991 0.7 0.2 -0.5 1.2 1.6 0.0 -1.1 1.7 0.2 -0.8 1.6 0.3 1992 -1.0 1.8 2.4 1.8 0.7 0.3 0.3 2.0 0.1 -1.4 2.5 1.1 1993 1.9 0.4 1.0 1.6 -3.7 -0.9 -0.2 0.1 -1.7 -3.9 2.5 2.1 1994 1.7 -0.7 4.1 1.4 -0.3 2.3 1.2 -0.6 0.2 -1.6 -0.2 1.6 1995 1.6 2.0 1.6 -1.9 -1.3 -2.4 -2.0 -0.7 0.3 -1.2 -3.3 -3.7 1996 -1.5 0.9 -2.8 -2.4 -1.8 0.7 2.0 0.4 0.8 1.5 1.2 -3.5 1997 -1.7 3.4 0.9 -1.7 -1.9 -3.5 1.5 0.8 -0.3 -3.1 -0.5 -1.0 1998 -0.6 0.6 0.4 0.5 0.0 -1.1 1.1 1.4 -2.2 1.6 0.8 1.5 1999 1.4 2.4 -0.2 -1.0 0.6 1.7 -1.1 -5.0 1.1 0.3 1.1 1.7 2000 0.5 2.9 0.2 -2.7 1.6 -0.3 -2.5 0.7 0.5 3.5 0.0 -2.1 2001 0.2 -0.5 -1.8 1.7 -0.5 -1.4 0.6 0.5 -2.7 0.6 1.9 -3.5 2002 0.6 1.5 0.4 2.6 1.8 1.8 2.3 0.5 -4.4 -2.6 0.9 -2.1 2003 0.4 1.1 0.2 -2.1 0.7 -0.8 0.2 -2.1 -0.7 0.0 1.1 -1.2 2004 -0.3 -1.6 1.1 1.9 0.8 -1.5 0.0 -1.3 2.5 -2.4 -0.2 2.7 2005 1.2 -0.5 -3.3 0.2 -1.1 -2.0 0.3 1.9 1.2-9999.0-9999.0-9999.0