| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1961 | ----- | z | 42.47 | h | 43.46 | d | 49.17 | 54.89 | 67.80 | 71.48 | 73.76 | 56.71 | a | 49.26 | 36.62 | 33.35 | 53.65 | |||||||||
| 1962 | 27.56 | 36.02 | 39.47 | b | 51.47 | 52.66 | 61.20 | 67.63 | 65.40 | 61.40 | 49.87 | 42.12 | 34.95 | 49.15 | ||||||||||||
| 1963 | 24.30 | c | 42.09 | a | 42.08 | 44.82 | 56.81 | 60.56 | v | 64.74 | 67.17 | d | 65.26 | a | 53.07 | a | 42.08 | 32.81 | 48.66 | |||||||
| 1964 | 34.21 | b | 36.43 | 39.27 | 45.85 | 52.69 | ----- | z | 69.19 | ----- | z | 57.15 | 52.97 | 38.82 | 34.04 | c | 46.06 | |||||||||
| 1965 | 33.66 | 39.32 | 39.97 | 50.62 | 53.55 | ----- | z | 68.18 | 67.45 | 55.18 | 53.84 | 44.83 | 31.00 | 48.87 | ||||||||||||
| 1966 | 34.19 | 35.61 | 42.56 | 51.10 | 59.21 | 61.87 | 68.55 | a | 68.13 | 62.35 | 50.38 | a | 44.40 | 36.89 | 51.27 | |||||||||||
| 1967 | 38.13 | 39.95 | 41.50 | c | 43.81 | a | 56.08 | a | 64.05 | 71.60 | 73.26 | b | 66.05 | 51.55 | b | 42.35 | 32.05 | a | 51.70 | |||||||
| 1968 | 33.77 | 43.10 | 47.32 | 46.30 | 55.98 | a | 64.45 | 72.86 | b | 65.77 | a | 61.10 | 49.66 | 40.80 | 35.08 | 51.35 | ||||||||||
| 1969 | 28.00 | 34.18 | 42.03 | 48.82 | 59.27 | 66.58 | 68.29 | 67.82 | 62.15 | 46.06 | 40.45 | 35.62 | c | 49.94 | ||||||||||||
| 1970 | 37.00 | c | 40.41 | 41.97 | 43.36 | a | 55.98 | 67.55 | 71.90 | 70.16 | 56.43 | 48.37 | 42.25 | 32.97 | 50.70 | |||||||||||
| 1971 | 35.48 | 38.07 | 39.42 | a | 47.60 | a | 56.11 | 59.63 | 70.50 | 74.31 | 56.87 | 46.73 | 39.28 | a | 32.23 | 49.69 | ||||||||||
| 1972 | 31.52 | 37.48 | 45.06 | 45.47 | 57.02 | 64.18 | 69.00 | 69.94 | 56.90 | 48.56 | 39.97 | 25.98 | 49.26 | |||||||||||||
| 1973 | 29.56 | 39.59 | 42.94 | 47.62 | 58.45 | 63.63 | 69.71 | 68.11 | 61.58 | 49.48 | 41.42 | 38.81 | 50.91 | |||||||||||||
| 1974 | 29.90 | 38.98 | 42.11 | 47.45 | 53.68 | 67.53 | 69.37 | 68.60 | 62.75 | 51.13 | 41.80 | 34.56 | 50.66 | |||||||||||||
| 1975 | 34.37 | 37.04 | 40.34 | 42.98 | 53.90 | 61.47 | 72.76 | 65.58 | 62.28 | 50.26 | 39.33 | 35.03 | 49.61 | |||||||||||||
| 1976 | 34.19 | 36.33 | 41.18 | 47.07 | 56.12 | e | 58.79 | i | 69.28 | k | 65.92 | 63.53 | 50.71 | 42.10 | 32.76 | 46.99 | ||||||||||
| 1977 | 25.89 | 40.04 | 40.56 | 52.00 | 51.81 | 66.08 | 69.42 | 72.29 | 58.79 | d | 50.32 | 37.95 | 37.66 | 50.23 | ||||||||||||
| 1978 | 36.55 | 40.23 | 47.31 | 48.58 | 52.06 | 63.73 | 69.92 | 67.77 | 58.40 | a | 51.79 | 33.37 | 25.52 | a | 49.60 | |||||||||||
| 1979 | 17.47 | 33.75 | 44.71 | 48.37 | 56.89 | 63.57 | 71.50 | 69.66 | 65.13 | 53.76 | 36.70 | 35.81 | o | 51.05 | ||||||||||||
| 1980 | 29.79 | 39.19 | 41.68 | 50.83 | 55.81 | 60.20 | 70.11 | 65.55 | 62.05 | 50.35 | 42.12 | d | 36.61 | 50.36 | ||||||||||||
| 1981 | 37.19 | 38.62 | 44.39 | 50.20 | 55.82 | 62.47 | 67.16 | 71.52 | 62.38 | 49.06 | 42.60 | 36.77 | 51.52 | |||||||||||||
| 1982 | 28.76 | 33.91 | 42.27 | 45.32 | 53.69 | 65.47 | 68.95 | 70.55 | 58.48 | 48.34 | 36.60 | 35.05 | 48.95 | |||||||||||||
| 1983 | 36.55 | 41.11 | 46.13 | 46.92 | 56.68 | 61.45 | 66.87 | 71.34 | 58.32 | 49.77 | 43.08 | 24.97 | 50.27 | |||||||||||||
| 1984 | 31.15 | 38.19 | 44.71 | 46.60 | 54.27 | 59.70 | 71.03 | 71.60 | 59.85 | 47.08 | 41.10 | 28.19 | 49.46 | |||||||||||||
| 1985 | 26.73 | 30.62 | 39.98 | 52.32 | 57.60 | 64.90 | 74.66 | 65.55 | a | 55.13 | 47.35 | 28.03 | 21.87 | 47.06 | ||||||||||||
| 1986 | 35.95 | 40.96 | 48.16 | 48.98 | 56.81 | 69.32 | 66.68 | 73.92 | 57.55 | 51.40 | k | 41.77 | 33.97 | 52.19 | ||||||||||||
| 1987 | 27.89 | 38.82 | 44.82 | 54.86 | a | 59.13 | 67.19 | c | 68.47 | 67.18 | 64.43 | 53.23 | 42.86 | a | 34.47 | 51.95 | ||||||||||
| 1988 | 32.05 | a | 39.21 | a | 42.15 | 52.17 | 56.94 | 64.11 | b | 70.37 | 67.71 | 61.18 | 59.02 | i | 41.06 | l | 31.66 | 51.75 | ||||||||
| 1989 | 29.90 | j | 25.43 | 44.03 | a | 52.87 | 55.06 | 65.66 | k | 71.43 | j | 67.10 | 59.44 | l | 49.20 | i | 39.06 | m | 32.13 | l | 48.90 | |||||
| 1990 | 37.40 | k | 36.04 | p | 44.21 | j | 54.75 | l | 53.90 | j | 64.17 | i | 73.12 | j | 70.42 | a | 66.00 | l | 49.46 | c | ----- | z | 27.06 | m | 59.94 | |
| 1991 | 28.26 | n | 42.58 | j | 39.97 | n | 47.74 | m | 52.26 | j | 59.09 | n | 71.18 | k | 71.70 | i | 64.58 | k | 50.16 | c | 41.94 | m | 35.56 | n | 50.16 | |
| 1992 | 37.89 | i | 42.53 | m | 47.59 | o | 53.62 | f | 61.62 | o | 68.35 | j | 68.60 | k | 71.19 | j | 63.34 | k | 51.39 | l | 38.77 | o | 32.77 | p | 9999.00 | |
| 1993 | 23.05 | u | 29.15 | k | 43.86 | i | 48.02 | 62.53 | l | 61.36 | b | 63.59 | n | 66.59 | i | 60.14 | i | 52.15 | k | 34.56 | n | 34.88 | n | 54.69 | ||
| 1994 | ----- | z | 35.73 | m | 46.62 | j | 50.32 | m | 59.39 | m | 63.50 | k | 74.21 | n | 70.03 | 65.56 | l | 48.15 | r | 36.44 | m | 30.71 | n | 70.03 | ||
| 1995 | 36.83 | m | 41.46 | n | 45.36 | b | 48.63 | k | 56.58 | m | 62.45 | b | 70.94 | m | 67.57 | i | 61.89 | k | 48.25 | i | 43.09 | m | 39.09 | o | 53.90 | |
| 1996 | 33.78 | o | 36.23 | n | 44.66 | l | 51.50 | k | 53.06 | m | 61.75 | n | 72.44 | m | 70.75 | k | 60.33 | o | 50.73 | i | 42.42 | q | 35.82 | n | 9999.00 | |
| 1997 | 32.06 | m | 37.66 | l | 46.97 | l | 48.71 | i | 61.50 | l | 62.20 | o | 68.47 | n | 72.70 | k | 63.72 | 49.50 | q | 43.12 | q | 33.97 | o | 63.72 | ||
| 1998 | 33.94 | m | 39.69 | j | 44.61 | l | 50.69 | l | 54.69 | r | 63.11 | b | 76.26 | j | 72.31 | j | 67.17 | i | 50.75 | q | 41.90 | o | 33.63 | p | 63.11 | |
| 1999 | 36.00 | m | 37.73 | m | 41.82 | i | 44.71 | m | 54.69 | m | 61.56 | l | 70.17 | m | 70.98 | e | 59.35 | j | 51.02 | h | 45.70 | j | 35.10 | k | 70.98 | |
| 2000 | 33.55 | i | 41.15 | i | 43.18 | i | 53.33 | j | 56.66 | i | 64.13 | g | 69.60 | j | 69.48 | i | 61.11 | g | 49.77 | i | 34.47 | j | 31.69 | o | 9999.00 | |
| 2001 | 33.83 | g | 36.79 | i | 45.02 | j | 47.57 | i | 58.74 | h | 62.82 | h | 69.79 | j | 72.39 | h | 63.84 | k | 49.96 | h | 42.86 | l | 34.25 | i | 9999.00 | |
| 2002 | 35.39 | i | 37.55 | i | 42.02 | i | 48.31 | i | 55.45 | i | 67.67 | i | 75.05 | i | 67.19 | 61.38 | j | 47.18 | 40.00 | l | 38.07 | j | 57.19 | |||
| 2003 | 39.18 | i | 37.38 | g | 47.86 | j | 49.50 | f | 58.88 | j | 66.38 | j | 78.58 | f | 72.98 | j | 64.63 | g | 54.72 | h | 38.54 | q | 36.05 | l | 9999.00 | |
| 2004 | 32.42 | k | 39.70 | g | 49.94 | g | 52.58 | f | 56.62 | k | 67.30 | g | 73.61 | i | ----- | z | 59.02 | g | 51.57 | j | 39.81 | l | 35.14 | i | 9999.00 | |
| 2005 | 34.86 | j | 37.38 | h | 44.35 | h | 47.95 | h | 57.38 | j | 60.84 | h | 73.83 | h | 70.67 | g | 60.72 | g | 52.98 | j | 37.17 | l | 30.35 | k | 9999.00 | |
| 2006 | 37.76 | j | 35.53 | h | 42.50 | g | 50.50 | l | 59.35 | g | 66.61 | l | 75.06 | n | 68.95 | l | 62.85 | m | 48.25 | k | 38.20 | o | 34.59 | n | 9999.00 | |
| 2007 | 30.17 | j | 39.06 | k | 45.84 | l | 48.55 | j | 60.10 | f | 65.50 | l | 77.58 | l | 70.82 | i | 60.39 | l | 50.95 | l | 38.47 | l | 34.78 | o | 9999.00 | |
| 2008 | 28.89 | m | ----- | z | 41.14 | i | 45.31 | l | 55.64 | q | 61.45 | k | 71.36 | i | 70.47 | 62.42 | l | ----- | z | 44.38 | m | 30.86 | i | 70.47 | ||
| 2009 | 32.95 | l | 38.59 | k | 40.00 | i | 47.98 | i | 56.53 | l | 67.38 | j | 73.45 | k | 74.54 | h | 67.00 | i | 47.13 | l | 41.22 | l | 27.90 | j | 9999.00 | |
| 2010 | 39.29 | n | 40.84 | i | 43.52 | i | 49.66 | k | 50.59 | n | 61.40 | i | 71.03 | m | 70.25 | i | 64.62 | j | 52.97 | l | 40.17 | l | 34.82 | l | 9999.00 | |
| 2011 | 34.12 | k | 36.16 | l | 43.03 | n | 46.09 | s | 54.36 | j | 63.19 | l | 70.28 | m | 72.84 | o | 68.26 | k | 54.09 | n | 40.80 | t | 30.95 | l | 9999.00 | |
| 2012 | 38.11 | v | 38.37 | j | 44.53 | p | 53.24 | k | 58.18 | n | 61.53 | l | 75.11 | l | 73.76 | h | 64.58 | l | 51.91 | n | 45.10 | t | 34.68 | q | 9999.00 | |
| 2013 | 28.20 | i | 37.35 | k | 45.62 | k | 54.50 | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 31.55 | 37.67 | 42.90 | 48.38 | 55.69 | 63.89 | 69.66 | 69.16 | 60.45 | 49.99 | 40.18 | 32.77 | 50.18 | |||||||||||||
| S.D. | 4.78 | 3.67 | 2.48 | 3.01 | 2.09 | 2.65 | 2.17 | 2.66 | 3.18 | 2.11 | 3.58 | 4.16 | 1.16 | |||||||||||||
| SKEW | -0.91 | -1.48 | 0.41 | 0.11 | -0.12 | 0.23 | 0.07 | 0.30 | -0.04 | 0.15 | -1.68 | -1.06 | -0.67 | |||||||||||||
| MAX | 38.13 | 43.10 | 48.16 | 54.86 | 59.27 | 69.32 | 74.66 | 74.31 | 66.05 | 53.84 | 44.83 | 38.81 | 51.95 | |||||||||||||
| MIN | 17.47 | 25.43 | 39.27 | 42.98 | 51.81 | 59.63 | 64.74 | 65.40 | 55.13 | 46.06 | 28.03 | 21.87 | 47.06 | |||||||||||||
| NO YRS | 27 | 28 | 30 | 30 | 29 | 27 | 27 | 33 | 29 | 29 | 27 | 27 | 20 | |||||||||||||