| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1955 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 32.18 | p | 27.86 | c | 27.86 | |
| 1956 | 24.43 | a | 21.17 | c | 34.85 | h | 47.62 | e | 57.55 | i | 58.40 | d | 71.90 | e | 68.40 | j | 61.08 | f | 44.26 | h | 34.40 | a | 28.33 | j | 42.99 | |
| 1957 | 14.82 | 26.93 | ----- | z | 44.58 | 53.84 | 60.73 | 68.32 | 68.09 | c | 65.97 | n | 47.15 | k | 32.67 | l | 29.43 | q | 48.19 | |||||||
| 1958 | 24.41 | c | 33.73 | b | 34.11 | 42.43 | 61.02 | a | ----- | z | ----- | z | ----- | z | 58.69 | a | 52.61 | 35.40 | d | 32.97 | 41.71 | |||||
| 1959 | 28.32 | a | 32.66 | c | 38.02 | h | 47.20 | e | 49.58 | g | 64.96 | f | 72.28 | d | 67.98 | d | 56.44 | c | 46.84 | f | 33.14 | e | 26.34 | f | 48.29 | |
| 1960 | 17.20 | i | 23.50 | m | 36.79 | b | 42.92 | f | 50.46 | c | 63.64 | i | 75.97 | b | 66.59 | c | 63.37 | g | 51.84 | o | 34.09 | m | 26.71 | l | 57.45 | |
| 1961 | 26.93 | i | 35.59 | k | 36.06 | n | 43.27 | f | 52.57 | p | 68.78 | e | 74.45 | i | 75.94 | e | 54.79 | a | 46.38 | b | 33.96 | f | 24.46 | q | 61.47 | |
| 1962 | 15.58 | l | 26.15 | k | 34.00 | p | 50.84 | k | 50.88 | r | 61.17 | c | 67.72 | b | 66.88 | b | 62.27 | f | 48.23 | c | 37.98 | d | 30.36 | m | 56.40 | |
| 1963 | 21.42 | g | 40.09 | a | 38.52 | i | 40.91 | c | 55.77 | i | 60.50 | m | 66.46 | e | 70.11 | 64.59 | h | 50.87 | h | 36.00 | f | 23.81 | g | 54.39 | ||
| 1964 | 22.35 | k | 25.04 | o | 31.67 | v | 43.04 | r | 54.05 | t | ----- | z | 69.40 | a | 64.30 | d | 56.56 | e | 50.81 | m | 32.43 | p | 26.81 | r | 63.42 | |
| 1965 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 61.08 | k | 68.14 | m | 61.44 | n | 53.00 | d | 51.30 | f | 39.80 | g | 26.26 | h | 53.00 | |
| 1966 | 28.85 | e | 28.62 | l | 39.02 | g | 46.06 | f | 55.86 | i | 59.19 | c | 69.15 | e | 68.98 | g | 64.22 | a | 47.48 | j | 37.94 | m | 27.37 | h | 55.35 | |
| 1967 | 28.52 | k | 34.35 | h | 37.44 | m | 40.95 | t | 56.63 | p | 60.58 | e | 73.35 | e | 75.36 | b | 66.65 | f | 45.74 | b | 37.23 | 24.00 | 52.71 | |||
| 1968 | 22.61 | c | 34.81 | 40.87 | a | 42.19 | c | 52.88 | k | 61.70 | b | 72.45 | 64.44 | d | 58.29 | a | 44.83 | b | ----- | z | ----- | z | 49.13 | |||
| 1969 | 21.82 | l | 23.61 | n | 33.42 | l | 45.78 | l | 56.82 | c | 60.15 | d | 68.57 | b | 68.46 | h | 59.06 | e | 42.81 | b | 35.65 | c | 30.57 | j | 53.84 | |
| 1970 | 25.83 | j | 36.75 | f | 36.55 | b | 39.15 | m | 51.60 | e | 62.98 | b | 70.44 | f | 72.32 | a | 53.71 | f | 43.87 | d | 36.33 | g | 23.52 | f | 53.46 | |
| 1971 | 27.75 | e | 32.23 | d | 32.00 | i | 44.27 | h | 54.40 | 56.82 | 70.25 | c | 75.78 | d | 53.48 | b | 44.80 | f | 34.67 | g | 21.82 | f | 52.96 | |||
| 1972 | 21.18 | i | 26.69 | c | 40.28 | d | 40.86 | b | 54.48 | d | 61.55 | b | 69.13 | a | 72.17 | d | 55.02 | f | 48.50 | l | ----- | z | ----- | z | 52.17 | |
| 1973 | 22.13 | p | 31.68 | q | 38.44 | g | 45.50 | e | 55.28 | h | 61.84 | e | 72.43 | c | 70.48 | d | 58.88 | j | 47.67 | g | 33.38 | i | 29.53 | o | 62.56 | |
| 1974 | 15.03 | l | 31.08 | i | 36.44 | m | 43.90 | f | 50.48 | d | 66.82 | 68.79 | 69.22 | d | 63.44 | f | 50.07 | d | 35.42 | j | 25.59 | d | 55.16 | |||
| 1975 | 23.00 | e | 26.74 | e | 32.09 | b | 37.63 | c | 49.68 | c | 58.07 | b | 71.88 | c | 64.47 | a | 59.98 | e | 46.54 | f | 33.42 | e | 28.82 | f | 45.69 | |
| 1976 | 26.62 | k | 25.80 | i | 31.10 | k | ----- | z | 54.68 | i | 57.62 | a | 70.38 | a | 64.91 | o | 60.78 | l | 47.70 | i | 37.33 | o | 27.53 | m | 64.00 | |
| 1977 | 18.71 | g | 33.00 | h | 35.38 | e | 50.38 | f | 47.69 | e | 65.86 | a | 68.47 | a | 70.56 | 57.05 | 48.56 | 34.59 | g | 31.40 | a | 53.12 | ||||
| 1978 | 27.20 | d | 32.05 | f | 42.33 | d | 43.94 | c | 48.28 | a | 60.32 | e | 68.97 | b | 66.11 | 55.63 | c | 49.69 | b | 31.35 | d | 20.16 | 46.73 | |||
| 1979 | 12.42 | g | 26.83 | m | 38.48 | b | 43.67 | c | 54.11 | c | 61.74 | g | 70.98 | 69.02 | d | 63.28 | 52.87 | d | 33.05 | b | 29.06 | e | 50.50 | |||
| 1980 | 23.90 | g | 31.98 | d | 37.34 | c | 47.72 | 53.23 | e | 55.95 | 68.80 | a | 64.87 | 58.85 | 47.65 | 34.98 | 29.76 | d | 48.28 | |||||||
| 1981 | 29.32 | 28.62 | b | 40.18 | c | 45.33 | d | 50.73 | 57.57 | 67.08 | 72.79 | e | 60.48 | 44.62 | b | 37.50 | a | 29.02 | 46.94 | |||||||
| 1982 | ----- | z | 23.75 | 36.90 | 40.23 | 50.40 | 61.12 | 65.79 | 69.40 | 56.68 | 45.13 | 29.92 | 25.37 | 45.88 | ||||||||||||
| 1983 | 27.32 | 31.52 | 39.05 | 41.62 | 53.44 | 57.50 | 64.37 | 69.61 | 57.05 | 48.84 | 35.20 | 18.65 | 45.35 | |||||||||||||
| 1984 | 20.40 | 22.81 | 35.00 | l | 41.27 | 49.21 | 55.87 | 69.84 | 70.00 | 54.70 | 42.08 | 32.73 | 17.27 | 43.29 | ||||||||||||
| 1985 | 18.10 | 20.66 | 29.98 | 48.42 | 53.56 | 61.42 | 73.94 | 63.59 | c | 48.71 | k | 42.90 | 22.57 | 12.52 | 40.70 | |||||||||||
| 1986 | 22.81 | 32.96 | 42.53 | 43.63 | 51.98 | 65.37 | 67.32 | t | 72.13 | 53.42 | 49.13 | 36.85 | 25.02 | 45.08 | ||||||||||||
| 1987 | 20.37 | 31.39 | 38.68 | 51.30 | 56.84 | 63.70 | 67.02 | 68.42 | a | 64.07 | 53.24 | 36.34 | b | 26.58 | 48.16 | |||||||||||
| 1988 | 23.05 | 29.02 | 36.74 | 46.90 | 52.79 | 63.68 | 72.02 | 69.79 | 59.42 | 57.10 | 34.08 | 23.44 | 47.33 | |||||||||||||
| 1989 | 19.44 | 18.07 | 35.60 | 48.22 | 51.05 | 62.83 | 70.73 | 64.98 | 59.12 | 47.82 | 35.33 | 28.89 | 45.17 | |||||||||||||
| 1990 | 29.10 | 28.77 | 40.63 | 51.55 | 50.68 | 60.70 | 72.69 | 70.58 | 67.95 | 45.44 | 35.43 | 26.00 | o | 50.32 | ||||||||||||
| 1991 | 24.92 | m | 34.84 | 37.11 | 44.12 | 49.23 | 56.52 | 71.79 | 72.95 | 62.94 | n | 49.58 | 33.27 | 26.42 | 47.58 | |||||||||||
| 1992 | 24.61 | 34.76 | 44.74 | 48.68 | 60.03 | 67.23 | 66.65 | 70.68 | 58.78 | 50.60 | 29.80 | 20.56 | 48.09 | |||||||||||||
| 1993 | 17.23 | 19.16 | 31.55 | j | 42.77 | 54.78 | v | 56.62 | 59.73 | 64.39 | 60.35 | 49.02 | 28.73 | 26.35 | 42.43 | |||||||||||
| 1994 | 28.47 | 26.50 | 39.63 | 47.72 | 56.44 | 61.37 | 73.94 | 71.98 | 62.40 | o | ----- | z | 23.67 | z | 23.28 | v | 50.75 | |||||||||
| 1995 | 22.83 | s | 39.07 | m | ----- | z | 42.78 | e | 51.53 | 57.50 | 67.97 | 65.52 | 62.43 | 44.77 | 36.44 | n | 24.68 | t | 56.07 | |||||||
| 1996 | 27.17 | s | 23.78 | t | 36.96 | s | 45.78 | l | 47.89 | 58.32 | 70.02 | 66.15 | 55.60 | 46.94 | 35.70 | 25.92 | 50.81 | |||||||||
| 1997 | 27.55 | 30.98 | a | 37.71 | 42.78 | 54.89 | 58.03 | 64.11 | 67.31 | 60.38 | 46.11 | 36.33 | 25.31 | 45.96 | ||||||||||||
| 1998 | 27.40 | k | 31.32 | q | 40.94 | n | 43.50 | j | 52.18 | l | 55.75 | 71.40 | 69.08 | 63.80 | 45.82 | 35.02 | 22.70 | a | 51.94 | |||||||
| 1999 | 29.79 | g | 21.23 | q | 39.67 | k | 42.08 | 49.77 | 57.83 | 65.80 | a | 68.07 | c | 57.33 | 47.97 | 38.73 | 24.59 | n | 53.45 | |||||||
| 2000 | 25.38 | e | ----- | z | 36.50 | f | 48.22 | 52.79 | 60.84 | a | 67.22 | a | 70.00 | 56.31 | a | 46.66 | 28.71 | f | 24.11 | i | 53.43 | |||||
| 2001 | 21.59 | d | 26.30 | f | 39.91 | c | ----- | z | 55.02 | a | 59.71 | a | 68.47 | 71.48 | 61.95 | 46.90 | a | 37.03 | a | 22.11 | q | 51.34 | ||||
| 2002 | ----- | z | ----- | z | 41.20 | z | 45.35 | 51.26 | 61.77 | 71.66 | 63.24 | 59.75 | 44.72 | a | 34.27 | 30.21 | 51.36 | |||||||||
| 2003 | 30.05 | 32.80 | 41.65 | 43.15 | 51.92 | 62.57 | 75.53 | 70.98 | 61.60 | 51.71 | 30.47 | 30.75 | e | 48.60 | ||||||||||||
| 2004 | 18.48 | g | 19.48 | g | 36.31 | 47.68 | 52.58 | 61.10 | 70.23 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 53.58 | ||||||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 24.25 | 28.99 | 38.14 | 44.79 | 52.57 | 60.56 | 69.63 | 69.00 | 58.84 | 47.66 | 34.06 | 25.43 | 46.95 | |||||||||||||
| S.D. | 4.21 | 5.51 | 3.28 | 3.30 | 3.13 | 3.22 | 3.16 | 3.33 | 3.49 | 3.34 | 3.32 | 4.80 | 1.33 | |||||||||||||
| SKEW | -0.49 | -0.34 | -0.38 | 0.14 | 0.78 | 0.57 | -0.52 | 0.14 | 0.43 | 0.67 | -1.50 | -0.83 | -0.20 | |||||||||||||
| MAX | 30.05 | 40.09 | 44.74 | 51.55 | 61.02 | 68.78 | 75.97 | 75.94 | 67.95 | 57.10 | 38.73 | 32.97 | 48.60 | |||||||||||||
| MIN | 14.82 | 18.07 | 29.98 | 37.63 | 47.69 | 55.75 | 59.73 | 63.24 | 53.00 | 42.08 | 22.57 | 12.52 | 45.17 | |||||||||||||
| NO YRS | 25 | 26 | 26 | 33 | 35 | 42 | 44 | 42 | 34 | 34 | 30 | 25 | 8 | |||||||||||||