Year |
Winter |
Spring |
Summer |
Fall |
|
D-J-F |
M-A-M |
J-J-A |
S-O-N |
Avg |
|
| 1881 | 6 | 15.3 | 26.2 | 18.4 | 16.49 |
| 1882 | 10.2 | 17.2 | 24.6 | 17.2 | 17.27 |
| 1883 | 7.1 | 15.3 | 25.7 | 17.6 | 16.45 |
| 1884 | 7.3 | 16.2 | 23.8 | 18.2 | 16.37 |
| 1885 | 5.1 | 14.6 | 25.3 | 15.1 | 15.04 |
| 1886 | 4.6 | 15.6 | 24.3 | 16.8 | 15.36 |
| 1887 | 6.9 | 16.5 | 24.8 | 16.1 | 16.07 |
| 1888 | 7.3 | 16.3 | 25.4 | 15.4 | 16.1 |
| 1889 | 6.1 | 16 | 24 | 15.9 | 15.52 |
| 1890 | 12.4 | 15.7 | 25.2 | 17.2 | 17.64 |
| 1891 | 7.8 | 15 | 24.8 | 15.7 | 15.83 |
| 1892 | 6.9 | 14.8 | 24.6 | 16 | 15.57 |
| 1893 | 5.3 | 16.1 | 25.1 | 16.5 | 15.77 |
| 1894 | 7.8 | 16.9 | 24.7 | 16.5 | 16.48 |
| 1895 | 4.6 | 15.3 | 25 | 17.1 | 15.52 |
| 1896 | 6.4 | 17.4 | 25.5 | 17.7 | 16.75 |
| 1897 | 6.4 | 16 | 25.4 | 18.1 | 16.5 |
| 1898 | 7.3 | 16.8 | 25.6 | 16 | 16.45 |
| 1899 | 5.4 | 16.9 | 26.4 | 17.4 | 16.54 |
| 1900 | 5.6 | 16 | 25.6 | 18.5 | 16.43 |
| 1901 | 6.5 | 14.8 | 25.4 | 15.4 | 15.51 |
| 1902 | 4 | 16.4 | 26.2 | 17.5 | 16.01 |
| 1903 | 6.5 | 16.3 | 24.5 | 15.8 | 15.76 |
| 1904 | 4.8 | 15.1 | 24.5 | 17.4 | 15.46 |
| 1905 | 3.8 | 17.5 | 25 | 17.3 | 15.91 |
| 1906 | 6.6 | 15.5 | 25 | 16.9 | 15.99 |
| 1907 | 8.6 | 16.1 | 25.3 | 16.5 | 16.63 |
| 1908 | 5.5 | 18 | 24.9 | 16.9 | 16.33 |
| 1909 | 8.8 | 15.7 | 25.1 | 17.7 | 16.8 |
| 1910 | 4.9 | 16.9 | 24.1 | 17.3 | 15.82 |
| 1911 | 7.8 | 16.5 | 25.3 | 17.6 | 16.81 |
| 1912 | 5.3 | 15.9 | 24.2 | 17.3 | 15.68 |
| 1913 | 8.2 | 16.2 | 25.5 | 16.5 | 16.62 |
| 1914 | 7 | 15.9 | 26.1 | 16.7 | 16.42 |
| 1915 | 5.9 | 15.4 | 25 | 18.2 | 16.15 |
| 1916 | 7.5 | 16.2 | 24.8 | 16.7 | 16.28 |
| 1917 | 7.6 | 15.6 | 24.5 | 15.2 | 15.73 |
| 1918 | 4.8 | 17.3 | 25.2 | 16.6 | 15.97 |
| 1919 | 7.5 | 16.2 | 24.9 | 19.2 | 16.95 |
| 1920 | 6.1 | 14.7 | 24.6 | 17.2 | 15.66 |
| 1921 | 7.6 | 17.5 | 25.6 | 18.3 | 17.26 |
| 1922 | 8.4 | 16.6 | 24.9 | 17.7 | 16.88 |
| 1923 | 8.6 | 15.2 | 24.7 | 16.8 | 16.33 |
| 1924 | 6.6 | 14.4 | 26 | 16.7 | 15.93 |
| 1925 | 8.1 | 17.3 | 26.8 | 18.1 | 17.6 |
| 1926 | 6.7 | 14.5 | 25.3 | 17.2 | 15.95 |
| 1927 | 9.2 | 17.4 | 24.4 | 18.7 | 17.43 |
| 1928 | 6.5 | 15 | 25.1 | 17.1 | 15.92 |
| 1929 | 7 | 17.4 | 25 | 16 | 16.37 |
| 1930 | 7.8 | 16.1 | 25.8 | 16.5 | 16.57 |
| 1931 | 6.4 | 14.2 | 26.2 | 19.9 | 16.67 |
| 1932 | 11.1 | 15.2 | 25.9 | 15.7 | 16.99 |
| 1933 | 8.6 | 16.7 | 25.3 | 18 | 17.13 |
| 1934 | 7.6 | 15.6 | 26 | 17.7 | 16.73 |
| 1935 | 6.4 | 17.2 | 25.9 | 17.6 | 16.79 |
| 1936 | 3.8 | 17.1 | 26.7 | 17.5 | 16.3 |
| 1937 | 8.9 | 15.8 | 26.4 | 15.1 | 16.54 |
| 1938 | 7.7 | 17.6 | 25.8 | 17.8 | 17.23 |
| 1939 | 7.8 | 16.5 | 26.1 | 17.6 | 17.01 |
| 1940 | 4 | 15 | 25.4 | 16.9 | 15.31 |
| 1941 | 6.6 | 16.1 | 26.2 | 19 | 16.98 |
| 1942 | 6.4 | 16.6 | 25.9 | 17.5 | 16.61 |
| 1943 | 7.6 | 16.3 | 27 | 16.1 | 16.73 |
| 1944 | 8 | 16.6 | 25.9 | 16.9 | 16.86 |
| 1945 | 6.9 | 17.8 | 25.9 | 17.6 | 17.03 |
| 1946 | 6.5 | 17.7 | 24.9 | 17.6 | 16.68 |
| 1947 | 6.8 | 15.2 | 25.2 | 17.5 | 16.16 |
| 1948 | 6.5 | 17.8 | 25.9 | 16.9 | 16.77 |
| 1949 | 10.3 | 16.4 | 25.5 | 17.2 | 17.33 |
| 1950 | 10.4 | 15.8 | 24.9 | 16.4 | 16.88 |
| 1951 | 6.9 | 16.1 | 26.3 | 16.7 | 16.49 |
| 1952 | 9.2 | 16.5 | 27 | 16.2 | 17.22 |
| 1953 | 8 | 17 | 25.8 | 17.3 | 17.02 |
| 1954 | 8 | 16.1 | 27.2 | 17.8 | 17.26 |
| 1955 | 7.3 | 18.3 | 25.2 | 17.1 | 16.96 |
| 1956 | 7.4 | 17 | 26 | 17 | 16.85 |
| 1957 | 10.9 | 16.8 | 26 | 16.6 | 17.59 |
| 1958 | 5.1 | 16.1 | 25.7 | 17.9 | 16.21 |
| 1959 | 6.8 | 16.7 | 26 | 17.4 | 16.72 |
| 1960 | 7.1 | 14.4 | 25.9 | 17.8 | 16.31 |
| 1961 | 6 | 14.9 | 23.8 | 17.3 | 15.5 |
| 1962 | 7.2 | 15.5 | 25 | 15.9 | 15.88 |
| 1963 | 3.8 | 17.1 | 24.4 | 16.9 | 15.54 |
| 1964 | 3.8 | 15.7 | 24.8 | 16.9 | 15.3 |
| 1965 | 7 | 16.3 | 23.8 | 16.8 | 15.98 |
| 1966 | 5.3 | 15.3 | 24.3 | 15.9 | 15.19 |
| 1967 | 6.1 | 17 | 23.1 | 14.5 | 15.18 |
| 1968 | 5.4 | 15.7 | 25.3 | 16.2 | 15.63 |
| 1969 | 5 | 15.4 | 25.6 | 16.2 | 15.55 |
| 1970 | 4.7 | 16.9 | 25.3 | 17.7 | 16.16 |
| 1971 | 7.2 | 14.6 | 24.8 | 17.6 | 16.07 |
| 1972 | 8.5 | 15.6 | 24.2 | 16.6 | 16.21 |
| 1973 | 6.8 | 15.5 | 25.2 | 18.5 | 16.49 |
| 1974 | 8.8 | 17.4 | 24.3 | 16.3 | 16.68 |
| 1975 | 7.9 | 15.8 | 24.8 | 17 | 16.35 |
| 1976 | 6.9 | 16.2 | 24.1 | 13.7 | 15.24 |
| 1977 | 3.3 | 17.1 | 25.7 | 16.9 | 15.75 |
| 1978 | 3.5 | 15.7 | 25.4 | 18.7 | 15.84 |
| 1979 | 5.4 | 17.2 | 25.7 | 17.3 | 16.38 |
| 1980 | 7 | 16.8 | 28.2 | 18 | 17.48 |
| 1981 | 6.5 | 16.8 | 26.9 | 16.9 | 16.78 |
| 1982 | 5.4 | 17 | 25.4 | 16.8 | 16.15 |
| 1983 | 7 | 14.7 | 26 | 16.3 | 16.01 |
| 1984 | 5.7 | 15 | 25.3 | 17.7 | 15.93 |
| 1985 | 7.1 | 17.6 | 25.5 | 19.4 | 17.39 |
| 1986 | 7.1 | 17.1 | 26.9 | 18.6 | 17.43 |
| 1987 | 6.8 | 16.7 | 26.8 | 17.4 | 16.93 |
| 1988 | 6.9 | 16.8 | 26.7 | 17 | 16.86 |
| 1989 | 8.8 | 17 | 25.9 | 17.7 | 17.35 |
| 1990 | 8.7 | 17.4 | 26.6 | 18.6 | 17.85 |
| 1991 | 8.6 | 18.3 | 26.1 | 17.5 | 17.63 |
| 1992 | 9.3 | 16.3 | 25 | 16.8 | 16.83 |
| 1993 | 7.5 | 16 | 27.9 | 18.1 | 17.38 |
| 1994 | 7.4 | 18.2 | 26.5 | 18.5 | 17.67 |
| 1995 | 8.8 | 19 | 26.3 | 15.7 | 17.44 |
| 1996 | 6.5 | 16.9 | 26.7 | 17.2 | 16.81 |
| 1997 | 9.4 | 16.3 | 24.2 | 16 | 16.48 |
| 1998 | 7.5 | 15.8 | 26.3 | 18.9 | 17.13 |
| 1999 | 9.5 | 16.4 | 25.9 | 17.7 | 17.38 |
| 2000 | 8.3 | 17.2 | 26.5 | 16.7 | 17.18 |
| 2001 | 6.2 | 16.3 | 25.2 | 17.9 | 16.43 |
| 2002 | 8.7 | 16.9 | 25.6 | 17.7 | 17.24 |
| 2003 | 6.4 | 16.7 | 25.1 | 18 | 16.54 |
| 2004 | 6.1 | 18 | 25.1 | 18.4 | 16.9 |
| 2005 | 8.1 | 15.3 | 25.6 | 18.5 | 16.88 |
| 2006 | 7.3 | 17.4 | 26.2 | 16.9 | 16.93 |
| 2007 | 8.4 | 17.8 | 27.3 | 18.3 | 17.93 |
| 2008 | 8.3 | 16.3 | 26.2 | 16.8 | 16.92 |
| 2009 | 8.1 | 16.6 | 26 | 17.1 | 16.96 |
| 2010 | 4.6 | 17.3 | - | - | - |
| 1880s | 16.07444 | ||||
| 1890s | 16.305 | ||||
| 1900s | 16.083 | ||||
| 1910s | 16.243 | ||||
| 1920s | 16.533 | ||||
| 1930s | 16.796 | ||||
| 1940s | 16.646 | ||||
| 1950s | 16.92 | ||||
| 1960s | 15.606 | ||||
| 1970s | 16.831 |