| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1931 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 51.25 | o | 37.67 | 31.42 | 14.43 | 11.94 | 23.86 | |||||
| 1932 | 8.61 | 13.25 | a | 25.26 | 31.60 | 36.87 | 44.93 | a | 46.03 | 40.65 | 34.10 | 26.94 | 24.47 | 2.96 | h | 30.25 | ||||||||||
| 1933 | 9.61 | 2.78 | a | 20.48 | 26.50 | 31.19 | 38.42 | f | 41.58 | 38.00 | 31.90 | j | ----- | z | ----- | z | 24.46 | c | 24.33 | |||||||
| 1934 | 26.10 | 27.70 | a | 31.68 | 30.70 | 36.84 | 39.00 | 52.48 | ----- | z | 28.56 | n | 29.19 | 24.47 | 7.29 | 30.55 | ||||||||||
| 1935 | 9.10 | 6.82 | 9.13 | 26.91 | h | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 25.70 | a | 13.37 | 12.03 | 12.69 | ||||||
| 1936 | 11.03 | 13.78 | b | 21.72 | b | 26.24 | m | 29.67 | z | ----- | z | ----- | z | ----- | z | 32.88 | m | ----- | z | 13.43 | 17.77 | 15.55 | ||||
| 1937 | -4.23 | 10.18 | 19.74 | ----- | z | ----- | z | 38.04 | b | 48.32 | 40.94 | m | 40.07 | b | 30.32 | 27.63 | 18.41 | b | 25.39 | |||||||
| 1938 | 15.54 | r | ----- | z | ----- | z | 25.29 | w | ----- | z | ----- | z | 50.53 | p | 49.88 | n | 53.15 | j | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1939 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1940 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1941 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1942 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1943 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1944 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1945 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1946 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1947 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1948 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1949 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1950 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1951 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1952 | ----- | z | ----- | z | 19.10 | a | 32.20 | 37.27 | a | 41.43 | 48.23 | 44.84 | 38.20 | 28.97 | 13.60 | 20.17 | b | 32.40 | ||||||||
| 1953 | 25.70 | a | 23.00 | 22.60 | a | 27.17 | 31.06 | n | 36.11 | b | 45.52 | b | 42.88 | e | 37.85 | d | 26.05 | i | 23.16 | e | 15.41 | b | 29.94 | |||
| 1954 | 22.10 | 24.62 | d | 22.77 | e | 28.93 | a | 37.61 | c | 41.04 | b | 48.93 | b | 42.54 | e | 36.14 | b | 30.68 | c | 26.71 | b | 13.39 | 31.29 | |||
| 1955 | 6.58 | 14.46 | 17.23 | a | 27.73 | 33.96 | c | 43.73 | 44.96 | d | 50.76 | b | 50.50 | h | 30.47 | p | 21.43 | 20.48 | d | 28.13 | ||||||
| 1956 | 20.31 | e | 11.75 | a | 21.71 | c | 30.56 | c | 40.41 | b | 40.68 | b | 49.48 | f | 44.88 | e | 36.18 | b | 28.74 | d | 17.73 | d | 15.38 | b | 28.03 | |
| 1957 | 4.65 | 17.93 | 26.06 | 27.61 | b | 36.82 | c | 41.62 | f | 43.88 | f | 43.96 | g | 41.04 | e | 33.11 | c | 21.22 | c | 21.28 | b | 25.52 | ||||
| 1958 | 14.92 | e | 28.68 | c | 23.97 | b | 30.50 | b | 41.30 | a | 45.38 | d | 48.00 | e | 51.26 | d | 38.11 | c | 31.14 | c | 22.81 | c | 25.68 | c | 33.48 | |
| 1959 | 24.14 | b | 20.68 | 24.19 | 30.54 | b | 32.32 | c | 44.65 | d | 49.70 | a | 48.44 | d | 39.88 | e | 32.32 | c | 19.26 | c | 13.97 | b | 31.67 | |||
| 1960 | 10.24 | b | 15.37 | b | 25.88 | e | 29.50 | d | 34.92 | g | 43.88 | f | 53.20 | f | 45.19 | d | 38.81 | c | 28.40 | f | 24.21 | a | 16.96 | c | 25.77 | |
| 1961 | 18.13 | 25.21 | d | 26.57 | c | 28.00 | e | 34.54 | g | 46.55 | a | 50.48 | b | 53.31 | b | 34.71 | b | 29.85 | d | 19.52 | g | 17.23 | e | 33.01 | ||
| 1962 | 8.79 | b | 21.19 | a | 22.37 | a | 31.56 | c | 34.83 | g | 41.32 | b | 44.86 | c | 43.76 | f | 40.36 | h | 31.07 | c | 25.15 | d | 22.33 | d | 27.63 | |
| 1963 | 12.11 | c | 28.50 | d | 25.32 | f | 24.06 | l | 40.33 | g | 42.28 | e | 45.45 | 48.03 | b | 46.41 | c | 37.54 | c | 27.00 | 18.30 | a | 33.96 | |||
| 1964 | 12.30 | a | 10.00 | a | 16.86 | c | 26.87 | 33.23 | 43.40 | 47.26 | 43.83 | b | 35.59 | c | 31.61 | 22.97 | a | 20.87 | 28.73 | |||||||
| 1965 | 18.26 | 23.32 | 20.65 | ----- | z | 33.70 | a | 42.67 | 48.00 | a | 46.60 | a | 33.90 | 31.19 | 27.33 | 17.43 | a | 31.19 | ||||||||
| 1966 | 17.80 | a | 15.62 | b | 26.00 | a | 28.57 | 39.17 | b | 41.76 | a | 46.43 | c | 46.34 | b | 42.26 | c | 29.86 | b | 27.93 | a | 20.97 | a | 31.89 | ||
| 1967 | 21.15 | e | 23.41 | a | 25.80 | a | 27.78 | c | 34.43 | a | 43.10 | a | 51.34 | b | 51.04 | c | 43.08 | d | 29.00 | b | 25.40 | 14.48 | 32.50 | |||
| 1968 | 15.93 | a | 28.57 | a | 25.52 | 23.23 | 34.39 | c | 42.11 | c | 49.83 | b | 46.68 | 38.04 | b | 30.04 | c | 28.17 | f | 17.67 | a | 32.00 | ||||
| 1969 | 20.66 | b | 19.96 | 21.93 | b | 28.31 | a | 37.17 | b | 44.86 | a | 49.00 | a | 45.97 | a | 39.72 | a | 26.94 | 19.93 | a | 20.77 | a | 31.27 | |||
| 1970 | 23.37 | a | 24.39 | 22.77 | 24.90 | a | 34.97 | 45.10 | 48.42 | 46.59 | b | 33.43 | b | 26.65 | 27.20 | 16.42 | 31.18 | |||||||||
| 1971 | 20.84 | 20.82 | 21.60 | a | 28.10 | 36.16 | 39.83 | 48.55 | 51.00 | e | 33.56 | e | 27.67 | a | 23.61 | b | 12.55 | 30.36 | ||||||||
| 1972 | 12.16 | 22.00 | 26.73 | a | 27.73 | 35.93 | a | 44.17 | 45.19 | 47.00 | 35.83 | 32.57 | c | 25.54 | b | 10.48 | 30.45 | |||||||||
| 1973 | 14.00 | a | 22.64 | 23.21 | b | 27.66 | a | 35.32 | 41.63 | 49.70 | a | 46.90 | b | 38.55 | a | 29.48 | 26.70 | 23.06 | 31.57 | |||||||
| 1974 | 15.35 | 20.82 | 24.68 | 28.80 | 30.33 | m | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 25.10 | ----- | z | 22.95 | ||||||
| 1975 | ----- | z | ----- | z | ----- | z | ----- | z | 35.19 | e | 42.00 | d | 53.32 | 45.43 | h | 40.28 | a | 30.81 | 21.10 | 19.48 | 34.60 | |||||
| 1976 | ----- | z | ----- | z | 16.03 | 28.97 | 37.97 | a | 41.07 | a | 52.62 | e | 45.17 | a | 42.61 | b | 29.94 | 24.48 | i | 15.29 | 34.41 | |||||
| 1977 | 10.50 | a | 22.74 | a | 21.62 | b | 31.41 | a | 33.33 | d | 48.75 | b | 46.48 | d | 49.07 | a | 39.27 | d | 33.15 | e | 25.70 | c | 23.83 | a | 32.16 | |
| 1978 | 23.90 | a | 22.48 | c | 28.90 | b | 31.17 | a | 33.76 | f | 41.17 | r | 48.72 | f | 41.07 | c | 37.17 | a | 30.14 | b | 18.93 | a | 10.97 | a | 27.19 | |
| 1979 | 4.35 | 22.74 | a | 25.87 | a | 28.64 | b | 37.21 | g | 43.29 | f | 48.00 | 46.94 | 40.40 | e | 33.72 | b | 15.60 | 22.04 | d | 28.83 | |||||
| 1980 | 17.04 | e | 26.26 | b | ----- | z | 32.37 | c | 34.71 | c | 37.61 | b | 48.17 | a | 41.60 | a | 37.50 | 33.17 | b | 26.62 | a | 22.00 | a | 32.46 | ||
| 1981 | 21.57 | a | 20.57 | 25.80 | a | 33.25 | b | 35.68 | c | 42.37 | 45.90 | b | 49.32 | 38.25 | b | 27.55 | 27.92 | d | 21.76 | j | 33.47 | |||||
| 1982 | 15.52 | 18.64 | 25.10 | 23.23 | 26.78 | v | 44.77 | 50.52 | 47.26 | 38.44 | l | 29.65 | 17.83 | 16.13 | 28.86 | |||||||||||
| 1983 | 21.46 | e | 25.82 | 29.71 | 26.77 | 36.61 | 42.77 | 47.29 | 52.13 | 35.73 | 33.26 | 28.37 | 15.03 | 32.91 | ||||||||||||
| 1984 | 10.23 | 15.86 | 27.42 | 27.80 | 37.63 | a | 40.78 | c | 52.23 | 53.42 | 34.62 | i | 24.50 | k | ----- | z | 11.52 | 30.76 | ||||||||
| 1985 | 9.26 | 12.75 | 21.21 | b | 29.54 | q | 38.68 | 44.66 | a | 54.26 | 43.16 | f | 34.35 | d | 24.90 | b | 13.07 | 7.65 | 26.08 | |||||||
| 1986 | 22.26 | 26.89 | 31.42 | 30.17 | 37.17 | a | 45.03 | 46.75 | k | 52.07 | a | 36.14 | a | 26.05 | j | ----- | z | ----- | z | 35.14 | ||||||
| 1987 | 13.94 | 23.93 | a | 28.10 | b | 33.94 | l | 36.68 | 44.70 | t | 44.48 | ----- | z | ----- | z | 30.48 | 22.37 | c | 13.44 | m | 28.57 | |||||
| 1988 | 16.21 | c | 21.86 | 22.76 | b | 31.90 | 36.45 | 46.03 | 48.50 | m | 47.84 | 40.27 | 39.23 | 24.10 | 16.35 | 31.18 | ||||||||||
| 1989 | 12.48 | 13.00 | 29.97 | 34.37 | 36.13 | 44.70 | 54.61 | 46.81 | 41.70 | j | 33.00 | 21.21 | k | 18.58 | l | 33.90 | ||||||||||
| 1990 | 22.32 | 16.43 | 27.13 | 36.20 | 36.00 | 45.33 | i | ----- | z | 52.48 | 46.57 | 30.45 | i | 23.83 | 7.97 | 29.88 | ||||||||||
| 1991 | 15.26 | 25.46 | 25.06 | 29.90 | 34.07 | a | 39.40 | 53.58 | ----- | z | 42.80 | 32.74 | 27.50 | j | 20.68 | 31.90 | ||||||||||
| 1992 | 20.16 | 27.72 | 29.61 | 35.27 | 40.33 | a | 47.40 | 49.29 | 51.48 | ----- | z | 36.55 | 20.97 | 15.19 | 34.00 | |||||||||||
| 1993 | 11.39 | 15.71 | 29.48 | 31.53 | 42.52 | 41.47 | 42.71 | 47.06 | 39.57 | i | 34.00 | a | 15.10 | 21.55 | 30.23 | |||||||||||
| 1994 | 23.03 | 18.71 | 28.87 | 33.40 | 40.19 | 45.37 | 55.52 | 52.97 | 43.33 | i | 32.77 | 19.60 | 17.94 | 33.49 | ||||||||||||
| 1995 | 25.48 | 27.40 | m | 28.06 | 30.93 | 39.55 | 43.70 | 50.42 | 47.39 | 44.48 | i | 31.61 | m | 31.23 | 22.81 | 35.51 | ||||||||||
| 1996 | 20.97 | 20.28 | 28.52 | 31.30 | 38.58 | 45.83 | 53.81 | 50.84 | 39.43 | 33.90 | 28.06 | m | 24.68 | 35.28 | ||||||||||||
| 1997 | 20.58 | 23.43 | 27.77 | 30.67 | 40.71 | 45.10 | 51.55 | 50.97 | 46.33 | 32.29 | 28.07 | 17.32 | 34.57 | |||||||||||||
| 1998 | 28.61 | 24.21 | 27.94 | 31.43 | 38.55 | ----- | z | 55.55 | 52.58 | 47.33 | 30.71 | j | 28.73 | 21.08 | s | 37.22 | ||||||||||
| 1999 | 17.75 | s | 21.96 | c | 27.62 | b | 29.00 | 33.54 | e | 43.82 | b | 48.38 | b | 50.37 | a | 40.50 | d | 30.82 | c | 30.09 | h | 16.18 | i | 36.22 | ||
| 2000 | 22.27 | a | 27.92 | d | 24.96 | c | 34.50 | b | 38.74 | 44.76 | a | 52.35 | e | 51.77 | a | 40.42 | f | 32.07 | a | 16.72 | e | 16.41 | i | 34.61 | ||
| 2001 | ----- | z | 16.16 | c | 27.17 | b | 36.59 | a | 46.14 | i | 48.50 | j | 55.29 | g | 55.89 | c | 44.17 | g | 33.04 | e | 24.65 | g | 18.64 | i | 33.77 | |
| 2002 | 17.84 | 18.39 | 24.74 | 31.63 | 35.48 | f | 46.65 | d | 54.70 | d | 47.88 | e | 42.43 | 28.00 | i | 23.77 | 22.06 | m | 34.23 | |||||||
| 2003 | 26.61 | 20.83 | e | 29.26 | 29.29 | f | 39.19 | 45.67 | 56.29 | 52.27 | i | 42.84 | k | 39.45 | k | ----- | z | ----- | z | 36.31 | ||||||
| 2004 | ----- | z | 17.93 | o | 27.47 | n | 31.77 | 37.33 | m | 44.00 | m | 53.12 | f | 50.79 | g | 38.15 | q | ----- | z | ----- | z | ----- | z | 31.77 | ||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 16.47 | 20.15 | 24.66 | 29.98 | 36.76 | 43.12 | 49.37 | 47.98 | 39.04 | 31.07 | 22.58 | 17.35 | 31.72 | |||||||||||||
| S.D. | 6.76 | 5.84 | 4.21 | 2.92 | 2.55 | 2.68 | 3.56 | 3.88 | 3.66 | 2.88 | 4.82 | 4.66 | 1.43 | |||||||||||||
| SKEW | -0.52 | -0.74 | -1.05 | 0.01 | 0.10 | -0.45 | 0.08 | -0.36 | 0.55 | 0.34 | -0.53 | -0.32 | -0.01 | |||||||||||||
| MAX | 28.61 | 28.68 | 31.68 | 36.59 | 42.52 | 48.75 | 56.29 | 55.89 | 47.33 | 39.23 | 31.23 | 25.68 | 34.57 | |||||||||||||
| MIN | -4.23 | 2.78 | 9.13 | 23.23 | 31.19 | 36.11 | 41.58 | 38.00 | 33.43 | 24.90 | 13.07 | 7.29 | 28.73 | |||||||||||||
| NO YRS | 53 | 54 | 55 | 50 | 44 | 46 | 47 | 46 | 41 | 46 | 47 | 47 | 14 | |||||||||||||