| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1953 | 66.82 | 66.59 | 68.11 | 69.43 | 72.47 | 76.40 | 79.83 | a | 79.47 | 78.08 | 76.06 | 74.75 | 67.85 | a | 72.99 | |||||||||||
| 1954 | 65.68 | 64.84 | 64.97 | 65.98 | 70.18 | a | 76.48 | a | 77.79 | c | 78.81 | b | 77.68 | 76.55 | b | 72.29 | a | 69.29 | 71.71 | |||||||
| 1955 | 66.21 | 65.32 | 64.80 | a | 67.55 | 73.08 | 77.78 | 78.16 | 77.90 | 77.67 | a | 75.08 | a | 70.93 | 67.60 | 71.84 | ||||||||||
| 1956 | 64.24 | j | 65.60 | 65.92 | 67.65 | 70.31 | 75.93 | a | 76.63 | 77.71 | 79.33 | 75.74 | 70.23 | 66.84 | 71.99 | a | ||||||||||
| 1957 | 62.65 | k | 64.96 | a | 66.44 | 66.97 | 70.87 | 76.90 | a | 78.95 | j | 78.89 | 77.97 | 71.52 | 68.73 | 68.85 | 71.21 | b | ||||||||
| 1958 | 65.77 | 64.46 | b | 65.10 | 67.84 | a | 70.90 | 73.37 | 76.27 | 78.67 | j | 79.08 | j | 75.44 | 70.40 | 67.24 | 69.68 | b | ||||||||
| 1959 | 62.87 | 64.11 | 67.63 | 65.27 | 69.74 | 75.38 | 78.24 | 79.35 | 78.80 | 73.60 | 69.95 | 68.71 | 71.14 | |||||||||||||
| 1960 | 67.60 | j | 63.84 | 65.79 | 67.62 | 71.92 | a | 77.83 | 78.03 | a | 78.93 | i | 78.97 | 73.79 | 71.53 | 67.61 | 71.69 | b | ||||||||
| 1961 | 65.71 | 67.84 | 66.44 | 62.95 | 68.02 | 74.98 | 77.32 | 78.39 | 79.08 | 74.95 | 72.98 | 69.47 | 71.51 | |||||||||||||
| 1962 | 65.02 | 65.14 | 65.89 | 65.97 | 69.11 | 72.98 | 76.76 | 79.23 | 79.80 | 76.11 | 73.57 | a | 68.53 | 71.51 | ||||||||||||
| 1963 | 66.47 | 64.79 | 66.56 | 67.00 | 72.05 | 76.93 | 77.06 | 78.52 | 80.03 | 77.84 | 73.45 | 66.62 | a | 72.28 | ||||||||||||
| 1964 | 68.81 | 68.31 | 66.92 | 65.38 | 70.76 | 74.75 | 77.53 | 77.84 | 78.77 | 76.58 | 71.55 | 65.58 | 71.90 | |||||||||||||
| 1965 | 63.02 | 64.93 | 65.08 | 65.62 | d | 67.86 | f | 74.40 | 76.97 | 78.40 | 77.60 | j | 75.69 | j | 71.39 | h | 66.74 | b | 69.39 | d | ||||||
| 1966 | 66.69 | 64.14 | 67.24 | 67.62 | 68.23 | 73.90 | j | 76.37 | 77.73 | 78.25 | 74.66 | 70.67 | 68.31 | j | 71.16 | b | ||||||||||
| 1967 | 69.00 | 64.61 | 62.58 | 68.15 | 69.77 | 74.60 | 76.74 | 79.06 | 80.15 | 77.90 | 74.47 | 68.77 | a | 72.15 | ||||||||||||
| 1968 | 64.34 | 62.76 | 63.66 | 65.23 | 70.92 | 75.35 | 78.94 | 80.48 | 78.80 | 73.44 | 67.60 | 67.55 | 70.76 | |||||||||||||
| 1969 | 63.11 | 65.25 | 66.02 | 69.90 | 74.63 | 75.17 | 78.97 | 78.56 | 78.05 | 74.77 | 70.52 | 68.57 | c | 71.96 | ||||||||||||
| 1970 | 65.42 | 65.38 | ----- | z | 70.18 | 70.69 | 79.13 | 79.34 | 79.76 | 77.88 | 74.97 | 72.15 | 71.84 | 73.34 | a | |||||||||||
| 1971 | 64.44 | 67.96 | ----- | z | 71.95 | 74.16 | 75.80 | 77.29 | 78.68 | 78.50 | ----- | z | 72.38 | 65.10 | 72.63 | b | ||||||||||
| 1972 | 64.69 | 65.05 | 63.85 | 66.42 | 71.19 | 75.57 | 77.87 | 79.02 | 78.28 | 73.44 | 72.42 | 66.29 | 71.17 | |||||||||||||
| 1973 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1974 | 67.50 | m | 71.43 | g | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 79.24 | l | 78.57 | b | ----- | z | ----- | z | ----- | z | 78.57 | k |
| 1975 | ----- | z | 66.98 | d | 68.40 | p | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 74.45 | ----- | z | 70.71 | j | |
| 1976 | 65.15 | u | ----- | z | 67.03 | 68.39 | u | ----- | z | ----- | z | 77.71 | n | ----- | z | 79.20 | ----- | z | 73.50 | x | ----- | z | 73.12 | j | ||
| 1977 | 63.27 | ----- | z | 64.55 | 67.53 | 72.05 | 77.52 | 77.16 | 78.08 | 77.30 | 76.05 | 69.85 | 65.95 | 71.76 | a | |||||||||||
| 1978 | ----- | z | 65.04 | 65.55 | 67.30 | 69.03 | 77.45 | 79.13 | ----- | z | 80.88 | 77.42 | 73.17 | ----- | z | 72.77 | c | |||||||||
| 1979 | 67.89 | 67.05 | 68.26 | ----- | z | 72.13 | 76.43 | ----- | z | ----- | z | 81.20 | 79.53 | 72.83 | ----- | z | 73.17 | d | ||||||||
| 1980 | ----- | z | ----- | z | 69.00 | 69.93 | 72.98 | 77.59 | a | 81.24 | 81.13 | a | 81.15 | 78.94 | 74.63 | 69.00 | 75.56 | b | ||||||||
| 1981 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1982 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 76.75 | s | 73.88 | 68.15 | 71.01 | j | ||
| 1983 | 65.69 | 65.95 | 65.55 | a | 67.32 | 71.58 | 79.50 | 81.24 | 79.77 | 81.69 | f | 80.15 | 75.21 | d | 69.50 | 72.86 | a | |||||||||
| 1984 | 67.92 | 69.50 | a | 69.10 | 73.73 | ----- | z | 82.20 | 82.89 | 83.18 | 81.53 | 77.24 | 77.44 | n | 68.21 | 75.55 | b | |||||||||
| 1985 | ----- | z | ----- | z | 67.81 | 69.95 | 75.19 | 79.28 | 79.55 | 80.97 | 81.02 | ----- | z | 71.57 | 69.34 | 74.96 | c | |||||||||
| 1986 | 67.81 | 65.09 | 66.23 | 68.22 | 67.84 | 77.28 | 79.69 | 80.44 | 79.53 | 77.60 | 73.27 | 70.08 | 72.76 | |||||||||||||
| 1987 | 67.29 | 65.70 | 67.32 | ----- | z | 71.90 | 76.52 | 81.40 | 83.50 | 80.95 | 77.05 | 73.65 | 69.53 | 74.07 | a | |||||||||||
| 1988 | 67.79 | 66.33 | 68.60 | 69.60 | ----- | z | 79.85 | ----- | z | 81.18 | ----- | z | 79.23 | ----- | z | 71.15 | 72.96 | d | ||||||||
| 1989 | 69.29 | 65.38 | 67.02 | ----- | z | 73.15 | 77.45 | 79.98 | 81.10 | 79.97 | 76.79 | 71.12 | 69.48 | 73.70 | a | |||||||||||
| 1990 | 67.53 | 65.18 | 68.08 | 66.57 | 72.08 | 77.12 | 79.66 | b | ----- | z | 81.47 | 77.32 | 71.95 | ----- | z | 72.69 | b | |||||||||
| 1991 | 66.52 | 64.25 | 67.53 | 70.88 | 73.42 | 77.73 | ----- | z | 81.75 | a | 81.48 | ----- | z | ----- | z | ----- | z | 72.95 | d | |||||||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 66.11 | 65.56 | 66.39 | 67.86 | 71.35 | 76.74 | 78.55 | 79.60 | 79.37 | 76.20 | 72.13 | 68.26 | 71.82 | |||||||||||||
| S.D. | 1.86 | 1.44 | 1.59 | 2.25 | 1.89 | 1.95 | 1.72 | 1.57 | 1.32 | 2.03 | 1.86 | 1.58 | 0.63 | |||||||||||||
| SKEW | -0.16 | 0.87 | -0.32 | 0.46 | -0.01 | 0.49 | 0.69 | 0.92 | 0.30 | -0.11 | -0.38 | 0.03 | 0.23 | |||||||||||||
| MAX | 69.29 | 69.50 | 69.10 | 73.73 | 75.19 | 82.20 | 82.89 | 83.50 | 81.53 | 80.15 | 75.21 | 71.84 | 72.99 | |||||||||||||
| MIN | 62.87 | 62.76 | 62.58 | 62.95 | 67.84 | 72.98 | 76.27 | 77.71 | 77.30 | 71.52 | 67.60 | 65.10 | 70.76 | |||||||||||||
| YRS | 27 | 31 | 32 | 30 | 30 | 32 | 29 | 28 | 31 | 29 | 31 | 29 | 13 | |||||||||||||