| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1924 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 21.69 | n | 10.42 | 10.42 | k | |
| 1925 | 12.45 | 14.00 | 17.19 | e | 19.63 | 29.77 | a | 34.79 | b | 33.50 | a | 29.21 | b | 27.67 | 25.29 | 17.90 | 15.94 | 23.11 | ||||||||
| 1926 | 9.39 | 14.43 | 17.61 | 23.47 | 29.06 | 39.60 | 42.71 | 46.23 | 39.82 | b | 34.65 | 32.21 | a | 14.58 | 28.65 | |||||||||||
| 1927 | 17.87 | 17.36 | 21.61 | 26.33 | 33.94 | 44.80 | 52.13 | 49.81 | 41.33 | 38.65 | 32.73 | 24.13 | 33.39 | |||||||||||||
| 1928 | 27.81 | 18.97 | 24.52 | 25.47 | 38.19 | 41.60 | 48.52 | 49.52 | 45.67 | 32.97 | 25.00 | 15.94 | 32.85 | |||||||||||||
| 1929 | 15.67 | a | 12.07 | 21.10 | 24.67 | 36.30 | a | 41.37 | 53.90 | 54.13 | 44.07 | 38.87 | a | 30.80 | 30.32 | 33.60 | ||||||||||
| 1930 | 15.39 | 21.86 | 17.35 | 27.63 | 27.00 | 42.73 | 49.93 | c | 47.84 | 40.37 | 31.48 | 25.37 | 20.84 | 30.65 | ||||||||||||
| 1931 | 16.40 | a | 15.73 | b | 21.26 | 29.07 | 36.81 | 42.93 | 54.29 | 51.26 | 38.77 | 34.03 | 20.00 | a | 16.13 | 31.39 | ||||||||||
| 1932 | 10.10 | a | 13.76 | 19.45 | 22.77 | 29.73 | a | 38.60 | 38.52 | 46.90 | 43.23 | 32.40 | a | 31.27 | 12.06 | 28.23 | ||||||||||
| 1933 | 12.65 | 12.00 | 21.81 | 29.60 | 34.94 | 51.23 | 62.74 | ----- | z | ----- | z | 37.77 | 26.27 | 23.00 | 31.20 | b | ||||||||||
| 1934 | 15.00 | 19.00 | 26.23 | 29.30 | 36.84 | 36.47 | 49.00 | 48.94 | 40.20 | 34.61 | 26.57 | 18.45 | 31.72 | |||||||||||||
| 1935 | 14.61 | 15.14 | 13.13 | 22.07 | 27.13 | 40.23 | 44.00 | 45.77 | 41.53 | 27.87 | 19.97 | 19.39 | 27.57 | |||||||||||||
| 1936 | 18.42 | 16.72 | 17.45 | 24.37 | 31.29 | 40.23 | 48.29 | 47.94 | 37.60 | 32.10 | a | 28.93 | a | 19.13 | 30.21 | |||||||||||
| 1937 | 3.23 | 15.64 | 18.26 | 20.73 | 31.87 | 40.93 | 50.52 | 51.48 | 45.13 | 33.77 | 28.40 | 22.87 | a | 30.24 | ||||||||||||
| 1938 | 18.27 | a | 13.36 | 13.39 | 23.20 | 28.32 | 38.13 | 46.20 | a | 48.81 | 43.53 | 32.00 | a | 17.03 | 21.29 | 28.63 | ||||||||||
| 1939 | 15.23 | 7.59 | a | 19.03 | 28.30 | 33.77 | 40.27 | 49.87 | 50.23 | 41.07 | 31.90 | 29.45 | a | 28.32 | 31.25 | |||||||||||
| 1940 | 17.48 | 16.28 | 19.97 | 23.60 | 35.71 | 45.30 | 49.10 | 50.45 | 40.00 | 34.81 | 24.47 | 22.26 | 31.62 | |||||||||||||
| 1941 | 15.32 | 17.93 | 15.29 | 18.03 | 31.94 | 37.17 | 47.52 | 45.10 | 37.17 | 28.94 | 27.87 | 18.87 | 28.43 | |||||||||||||
| 1942 | 16.32 | 10.79 | 12.65 | 21.27 | 25.52 | 38.80 | 49.87 | 48.90 | 40.53 | ----- | z | 26.14 | a | 22.06 | 28.44 | a | ||||||||||
| 1943 | 17.61 | 15.36 | 19.55 | 28.67 | 32.03 | 35.67 | 47.10 | 47.13 | 44.33 | 34.39 | 29.27 | 17.16 | 30.69 | |||||||||||||
| 1944 | 12.61 | 8.66 | 13.94 | 19.00 | 30.90 | 34.73 | 42.90 | 46.03 | 39.80 | 32.71 | 19.67 | 15.48 | 26.37 | |||||||||||||
| 1945 | 9.68 | 11.44 | c | 11.40 | a | 20.74 | c | 28.93 | a | 36.48 | c | 48.97 | 45.87 | 42.60 | 36.97 | 25.87 | 20.40 | a | 28.28 | |||||||
| 1946 | 13.40 | a | 13.07 | 18.28 | b | 26.40 | 32.06 | 33.13 | 39.13 | 41.90 | 34.87 | 21.65 | 11.80 | 11.67 | j | 25.97 | a | |||||||||
| 1947 | 5.05 | j | 19.62 | g | 22.37 | l | 23.90 | i | 34.28 | m | 36.67 | i | ----- | z | 41.52 | j | 37.55 | j | 32.27 | i | 20.16 | e | 9.85 | e | 15.00 | j |
| 1948 | 16.47 | a | 8.86 | h | 11.39 | h | 23.90 | i | 26.64 | i | 36.65 | g | 48.30 | h | 46.56 | m | 38.62 | v | 34.67 | j | 26.25 | j | 15.46 | g | 16.47 | k |
| 1949 | -2.10 | j | 9.74 | i | 13.30 | h | 24.85 | j | 28.05 | j | 40.05 | h | 46.73 | i | 44.59 | i | 41.95 | k | 28.43 | h | 28.29 | i | 14.76 | j | ----- | z |
| 1950 | 9.48 | j | 14.05 | i | 19.48 | f | 23.67 | f | 24.00 | h | 36.68 | e | 46.91 | h | 44.56 | d | 36.26 | c | 35.81 | d | ----- | z | ----- | z | 38.33 | h |
| 1951 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1952 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1953 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1954 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1955 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1956 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1957 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1958 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1959 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1960 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1961 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1962 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1963 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1964 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1965 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1966 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1967 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1968 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1969 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1970 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1971 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1972 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1973 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1974 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1975 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1976 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1977 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1978 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1979 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1980 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1981 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1982 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1983 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1984 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1985 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1986 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1987 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1988 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1989 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1990 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1991 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1992 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1993 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1994 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1995 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1996 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1997 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1998 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1999 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2000 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2001 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2002 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2003 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2004 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2005 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2006 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2007 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2008 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2009 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2010 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 14.84 | 14.60 | 18.20 | 24.29 | 31.91 | 39.65 | 47.67 | 47.18 | 40.25 | 32.89 | 25.09 | 19.08 | 29.83 | |||||||||||||
| S.D. | 4.56 | 3.43 | 3.84 | 3.56 | 3.56 | 4.09 | 6.09 | 4.85 | 4.00 | 4.15 | 5.45 | 5.10 | 2.59 | |||||||||||||
| SKEW | 0.16 | -0.06 | 0.07 | -0.04 | 0.06 | 0.86 | -0.09 | -2.31 | -1.36 | -0.97 | -0.65 | 0.18 | -0.74 | |||||||||||||
| MAX | 27.81 | 21.86 | 26.23 | 29.60 | 38.19 | 51.23 | 62.74 | 54.13 | 45.67 | 38.87 | 32.73 | 30.32 | 33.60 | |||||||||||||
| MIN | 3.23 | 7.59 | 11.40 | 18.03 | 25.52 | 33.13 | 33.50 | 29.21 | 27.67 | 21.65 | 11.80 | 9.85 | 23.11 | |||||||||||||
| YRS | 23 | 22 | 22 | 22 | 22 | 23 | 22 | 22 | 22 | 22 | 23 | 23 | 19 | |||||||||||||