| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1948 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 74.74 | 70.71 | 65.02 | 51.95 | 35.48 | 25.05 | 53.83 | f | ||||||
| 1949 | 12.44 | 22.12 | 37.02 | 52.52 | 56.47 | b | 67.88 | m | 75.02 | h | 70.79 | c | 67.95 | 50.95 | 47.47 | 30.91 | b | 44.86 | b | |||||||
| 1950 | 26.16 | 38.88 | 43.05 | 51.58 | 59.48 | 65.23 | 71.19 | b | 72.14 | c | 62.33 | a | 57.12 | c | 44.78 | c | 41.00 | p | 53.81 | a | ||||||
| 1951 | 29.25 | i | ----- | z | 41.95 | 54.77 | f | 59.71 | 67.19 | d | 76.09 | b | 71.50 | e | 67.63 | c | 52.70 | a | 40.62 | b | 28.63 | 56.22 | c | |||
| 1952 | 23.71 | 33.28 | 44.50 | t | 51.42 | 62.10 | b | 67.30 | c | 74.21 | e | 73.82 | q | 66.26 | g | 58.67 | j | 44.69 | v | 34.22 | v | 52.00 | f | |||
| 1953 | 38.21 | 37.84 | 44.18 | 50.35 | 52.15 | 66.17 | a | 76.87 | a | 70.77 | 66.84 | b | 51.93 | a | 42.67 | a | 32.24 | 52.52 | ||||||||
| 1954 | 33.90 | 42.63 | a | 40.97 | 56.23 | 63.50 | 69.88 | a | 78.48 | 71.16 | 65.36 | a | 53.21 | 44.48 | 32.10 | a | 54.33 | |||||||||
| 1955 | 21.63 | 33.21 | 41.76 | d | 47.64 | a | 57.44 | ----- | z | 74.21 | e | ----- | z | ----- | z | 55.53 | a | 41.13 | ----- | z | 46.57 | d | ||||
| 1956 | 36.76 | d | 33.78 | 44.60 | a | 50.37 | 59.82 | 69.55 | 72.42 | 69.72 | a | 66.60 | 52.48 | 40.77 | 34.91 | t | 54.26 | a | ||||||||
| 1957 | 25.61 | i | 41.59 | 44.32 | c | 50.57 | i | 51.95 | 68.08 | 70.16 | c | 70.47 | a | 65.36 | l | 49.53 | 38.25 | ----- | z | 54.29 | d | |||||
| 1958 | 35.85 | r | 40.35 | a | 38.70 | a | 48.79 | a | 61.52 | e | 69.94 | f | 74.33 | e | 74.88 | g | 66.88 | f | 59.23 | g | 42.46 | c | 39.98 | a | 49.45 | e |
| 1959 | 36.73 | 32.00 | 45.50 | e | 54.19 | i | 57.40 | 71.17 | 77.64 | b | 73.36 | f | 63.17 | 55.19 | 44.30 | 36.60 | 51.97 | b | ||||||||
| 1960 | 28.34 | 36.28 | 48.56 | 53.60 | 60.84 | 74.63 | 75.08 | 73.68 | a | 68.23 | b | 52.89 | 40.60 | 35.56 | 54.02 | |||||||||||
| 1961 | 34.97 | 40.20 | c | 44.74 | d | 51.61 | h | 59.10 | 75.11 | c | 77.54 | e | 71.71 | 61.97 | 52.67 | b | 38.58 | 34.19 | b | 53.71 | a | |||||
| 1962 | 33.37 | 37.68 | n | 39.52 | 55.32 | 55.37 | e | ----- | z | ----- | z | ----- | z | 65.68 | 56.12 | a | 44.83 | ----- | z | 50.03 | e | |||||
| 1963 | 26.12 | o | 44.05 | 41.23 | a | 45.62 | b | 60.00 | b | 62.72 | a | 72.77 | c | 71.48 | d | 65.84 | e | 56.36 | b | 41.27 | b | 36.72 | a | 54.37 | a | |
| 1964 | 30.69 | 36.84 | 38.50 | 48.22 | e | 58.34 | b | 67.67 | a | 74.60 | k | 73.15 | h | 63.86 | a | 57.63 | d | 36.37 | 35.55 | 47.37 | b | |||||
| 1965 | 36.27 | 41.86 | j | 42.06 | 47.83 | 55.74 | ----- | z | 71.75 | a | 70.71 | 60.22 | 57.11 | 43.82 | 32.83 | e | 51.83 | b | ||||||||
| 1966 | 29.08 | ----- | z | 46.15 | 54.10 | 63.40 | 68.28 | a | 73.65 | a | 74.44 | 64.67 | 57.55 | k | 45.20 | j | 36.34 | c | 56.68 | c | ||||||
| 1967 | 32.65 | 37.48 | 44.13 | 40.43 | 58.15 | 64.73 | b | 75.79 | 75.33 | a | 65.18 | b | 55.84 | 44.67 | a | ----- | z | 54.03 | a | |||||||
| 1968 | 33.05 | 42.64 | 43.39 | 49.30 | 59.79 | e | 71.22 | 75.62 | c | 69.29 | 64.88 | 54.44 | ----- | z | 26.96 | h | 56.36 | b | ||||||||
| 1969 | 32.89 | 28.74 | a | 36.31 | 50.82 | 61.80 | a | 65.27 | b | ----- | z | 74.21 | n | 66.74 | e | 49.80 | k | 41.35 | 34.06 | 46.44 | c | |||||
| 1970 | 32.63 | 40.86 | 41.74 | n | 45.05 | a | 61.68 | 69.34 | b | 76.38 | c | 75.57 | a | 62.72 | 51.25 | a | 41.77 | 27.08 | 53.12 | a | ||||||
| 1971 | 35.23 | ----- | z | 43.81 | 49.70 | 54.37 | ----- | z | 76.48 | d | ----- | z | 63.90 | 47.22 | d | 39.53 | a | 27.71 | 48.66 | c | ||||||
| 1972 | 31.53 | a | 39.31 | 50.61 | 51.74 | c | 60.13 | 69.38 | 78.13 | 73.23 | 63.19 | a | 51.12 | j | 38.72 | a | 28.98 | g | 55.60 | b | ||||||
| 1973 | 24.82 | l | 33.59 | e | 38.88 | b | 50.17 | f | 61.80 | c | 66.23 | s | 75.43 | d | 71.52 | b | 63.71 | a | ----- | z | 38.96 | c | 35.72 | h | 54.84 | e |
| 1974 | 28.48 | 37.25 | 45.71 | 49.93 | 63.89 | q | 68.54 | d | 73.55 | a | 70.50 | 71.32 | s | 53.68 | f | 41.35 | 31.98 | 49.70 | c | |||||||
| 1975 | 33.10 | a | 35.26 | a | 40.43 | a | 42.53 | 58.00 | i | 69.19 | q | 75.78 | a | 73.03 | 66.18 | 49.32 | c | 39.64 | a | 40.29 | x | 50.59 | c | |||
| 1976 | 37.12 | c | 37.83 | i | 41.48 | 45.30 | g | 60.18 | 64.59 | s | 73.29 | c | 66.86 | i | 63.58 | e | 52.72 | d | 43.67 | a | 33.42 | f | 53.15 | e | ||
| 1977 | 33.12 | c | 40.18 | 37.97 | 52.65 | d | 52.23 | c | 66.37 | k | 73.38 | s | 72.04 | s | 62.26 | k | 56.80 | u | 44.05 | s | 37.08 | f | 43.23 | g | ||
| 1978 | ----- | z | 37.21 | 45.40 | 44.96 | c | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 57.98 | e | ----- | z | ----- | z | 46.39 | h | ||
| 1979 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 39.30 | 35.29 | 37.30 | j | ||
| 1980 | 36.87 | 39.53 | 39.53 | 51.18 | 54.23 | 65.45 | 75.26 | 72.90 | 64.70 | 54.47 | 42.65 | 39.32 | 53.01 | |||||||||||||
| 1981 | 36.73 | 39.57 | 42.28 | a | 54.28 | 59.61 | 73.82 | 76.27 | 74.81 | 67.95 | 49.92 | 41.88 | 35.13 | 54.35 | ||||||||||||
| 1982 | 29.34 | 39.13 | a | 40.35 | 49.14 | b | 59.86 | c | 65.85 | d | 72.95 | a | 71.35 | g | 63.46 | d | ----- | z | ----- | z | ----- | z | 52.51 | d | ||
| 1983 | 32.97 | m | 38.54 | e | 41.86 | f | 44.50 | n | ----- | z | ----- | z | 71.19 | m | 69.10 | 65.26 | a | 53.48 | b | 40.83 | a | 35.68 | 50.48 | f | ||
| 1984 | 36.73 | 38.34 | a | 46.29 | 50.04 | e | 65.87 | a | 68.63 | 74.55 | 71.21 | l | 66.45 | 49.27 | 38.58 | 27.80 | a | 51.14 | a | |||||||
| 1985 | 31.58 | 36.91 | 40.64 | b | 55.90 | ----- | z | ----- | z | 76.96 | e | 72.55 | 60.45 | a | 53.10 | b | ----- | z | ----- | z | 53.51 | d | ||||
| 1986 | ----- | z | 41.91 | 48.46 | c | 51.20 | c | 62.07 | d | 72.98 | f | 73.87 | e | 74.31 | e | 59.13 | d | 51.32 | a | 42.47 | a | 34.55 | t | 56.08 | c | |
| 1987 | ----- | z | ----- | z | 43.28 | b | 54.66 | a | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 50.94 | v | 40.14 | b | 30.41 | h | 46.02 | i |
| 1988 | ----- | z | ----- | z | 42.33 | y | 53.28 | u | 50.19 | o | 65.48 | i | 75.67 | y | 72.43 | d | 63.95 | h | ----- | z | 40.23 | d | 29.33 | d | 47.33 | i |
| 1989 | 28.31 | 35.74 | a | 48.62 | e | 59.43 | g | 60.54 | h | 69.67 | c | 77.55 | a | 71.98 | a | 65.07 | c | 52.72 | d | 43.88 | a | 37.44 | g | 54.84 | c | |
| 1990 | 32.72 | a | 36.11 | 47.77 | a | 55.10 | a | 59.11 | d | 70.77 | b | 76.42 | a | 72.15 | 66.07 | c | 55.35 | a | 42.74 | c | 28.26 | b | 53.55 | |||
| 1991 | 34.63 | a | 43.80 | f | 39.07 | c | 50.19 | a | 57.34 | f | 68.30 | b | 74.53 | l | 73.56 | e | 66.14 | i | 57.86 | c | 42.40 | 34.03 | 50.01 | d | ||
| 1992 | 26.97 | a | 40.22 | b | 44.60 | e | 57.19 | c | 64.72 | a | 68.10 | d | 72.14 | c | 74.18 | c | 66.75 | b | 57.77 | c | 39.98 | a | 29.79 | 53.53 | ||
| 1993 | 30.08 | 35.54 | 47.82 | a | 52.71 | d | 60.86 | c | ----- | z | 74.20 | a | 71.24 | j | 63.02 | j | 53.65 | g | 37.78 | 32.47 | p | 48.43 | e | |||
| 1994 | 35.05 | c | 34.97 | k | 47.64 | m | 52.65 | g | 59.04 | h | 70.06 | l | 77.88 | k | 75.93 | q | 64.96 | e | 51.63 | h | 32.31 | a | 31.86 | i | 44.11 | i |
| 1995 | ----- | z | 43.62 | c | 43.53 | 48.64 | a | 54.66 | b | 62.45 | b | 75.08 | 72.93 | d | 67.17 | d | 55.19 | e | 48.02 | e | 35.88 | e | 55.20 | a | ||
| 1996 | 36.26 | h | 41.56 | c | 45.92 | a | 54.88 | d | 60.43 | p | 69.68 | p | 76.56 | d | 75.40 | 64.29 | a | 52.60 | a | 41.39 | b | 38.00 | m | 56.58 | d | |
| 1997 | 34.97 | b | 39.54 | b | ----- | z | ----- | z | ----- | z | 69.18 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 28.44 | 43.03 | h | ||
| 1998 | 34.16 | f | 33.23 | 43.62 | a | 46.24 | e | 52.17 | b | 63.12 | 75.74 | 74.52 | g | 65.08 | 49.33 | b | 38.95 | 32.09 | b | 49.96 | b | |||||
| 1999 | 36.52 | b | 37.23 | 42.37 | d | 47.30 | 60.42 | e | 68.92 | 73.96 | e | 70.52 | 64.93 | o | 58.05 | b | 47.17 | ----- | z | 54.25 | b | |||||
| 2000 | 46.05 | i | 48.84 | a | 55.18 | c | 61.89 | l | 68.17 | e | 71.88 | j | 74.37 | 72.66 | f | ----- | z | 45.00 | x | 37.14 | b | 37.21 | q | 56.74 | g | |
| 2001 | 29.91 | h | 32.80 | 45.94 | d | 49.27 | d | 68.73 | i | 73.25 | h | ----- | z | 76.16 | ----- | z | ----- | z | 49.93 | b | 51.71 | x | 50.82 | g | ||
| 2002 | ----- | z | 37.24 | e | ----- | z | 56.47 | n | 64.21 | g | 74.44 | e | 77.21 | b | 74.07 | a | 66.07 | 53.69 | 42.93 | i | 33.48 | g | 63.79 | f | ||
| 2003 | 40.73 | e | 37.37 | b | 46.96 | h | 47.17 | c | 62.19 | j | 72.97 | m | 80.25 | q | 73.25 | g | 68.13 | 60.65 | r | ----- | z | ----- | z | 48.35 | h | |
| 2004 | 33.05 | b | 34.70 | b | 51.29 | 52.82 | b | ----- | z | ----- | z | 73.86 | b | 72.84 | f | 63.38 | f | 54.48 | i | 39.66 | a | 33.95 | c | 45.62 | e | |
| 2005 | 34.83 | v | ----- | z | 41.42 | y | 48.11 | c | 60.33 | d | ----- | z | 77.69 | w | 72.07 | j | 61.19 | n | 50.33 | y | 45.35 | d | 35.45 | u | 51.26 | i |
| 2006 | 29.50 | p | 36.91 | k | 37.91 | d | 50.24 | a | 62.82 | i | 70.73 | q | ----- | z | 72.05 | i | 65.00 | s | 51.28 | d | 41.78 | a | 33.77 | a | 42.99 | g |
| 2007 | 31.53 | b | 39.14 | c | 48.93 | a | 51.05 | i | 63.60 | p | 74.07 | w | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 39.87 | i |
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 32.20 | 37.66 | 43.56 | 50.39 | 59.16 | 68.44 | 74.96 | 72.42 | 64.91 | 53.53 | 41.47 | 32.78 | 53.62 | |||||||||||||
| S.D. | 5.13 | 4.35 | 3.99 | 3.66 | 3.78 | 3.27 | 1.94 | 1.88 | 2.17 | 2.85 | 3.29 | 3.72 | 0.68 | |||||||||||||
| SKEW | -1.61 | -0.75 | 0.47 | -0.40 | -0.17 | 0.22 | -0.33 | 0.20 | -0.68 | -0.08 | 0.07 | -0.18 | -0.40 | |||||||||||||
| MAX | 40.73 | 48.84 | 55.18 | 57.19 | 68.17 | 75.11 | 78.48 | 76.16 | 68.23 | 58.05 | 49.93 | 39.98 | 54.35 | |||||||||||||
| MIN | 12.44 | 22.13 | 36.31 | 40.43 | 51.95 | 62.45 | 70.16 | 69.10 | 59.13 | 47.22 | 32.31 | 25.05 | 52.52 | |||||||||||||
| YRS | 40 | 46 | 49 | 44 | 40 | 32 | 42 | 35 | 40 | 39 | 49 | 31 | 7 | |||||||||||||