| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1959 | ----- | z | ----- | z | ----- | z | 31.03 | 34.55 | 46.37 | 50.67 | a | 46.46 | c | 39.13 | 31.57 | h | 20.10 | 11.39 | 34.96 | |||||||
| 1960 | 12.48 | 20.90 | 28.87 | 31.17 | 36.42 | 44.44 | c | 52.35 | 45.14 | b | 39.17 | 30.29 | 25.17 | 17.52 | 31.99 | |||||||||||
| 1961 | 18.71 | 28.82 | 27.50 | a | 28.45 | a | 35.57 | a | 47.22 | c | 49.33 | a | 50.93 | a | 35.77 | 30.48 | d | 19.97 | a | 18.63 | a | 32.62 | ||||
| 1962 | 6.86 | c | 20.82 | 24.93 | d | 31.55 | a | 36.00 | 41.59 | a | 43.46 | c | 44.27 | e | 39.84 | k | 30.42 | 27.33 | 22.90 | a | 30.01 | |||||
| 1963 | 12.74 | 30.46 | 25.10 | 29.17 | 40.37 | a | 43.59 | c | 44.84 | 45.65 | 44.00 | c | 34.35 | 27.03 | 18.65 | 33.00 | ||||||||||
| 1964 | 19.19 | 18.31 | 23.54 | c | 27.31 | a | 34.84 | 42.70 | 49.94 | 45.13 | a | 36.21 | a | 28.84 | 22.52 | a | 23.60 | a | 31.01 | |||||||
| 1965 | 23.23 | a | 25.36 | 23.39 | 34.63 | 35.23 | 45.10 | 47.58 | 47.30 | a | 34.96 | b | 31.77 | a | 27.87 | 15.03 | b | 32.62 | ||||||||
| 1966 | 18.10 | 21.11 | 24.48 | b | 28.87 | 37.47 | a | 43.60 | 46.93 | b | 46.83 | b | 41.67 | 29.33 | a | 29.83 | 23.00 | b | 32.60 | |||||||
| 1967 | 25.13 | 24.56 | a | 25.23 | a | 26.37 | 37.03 | a | 44.93 | 52.35 | 49.16 | 42.83 | 29.68 | 27.27 | 16.19 | 33.39 | ||||||||||
| 1968 | 17.81 | 27.14 | 25.74 | 25.10 | 36.19 | 42.47 | 47.58 | 45.71 | 37.93 | 29.03 | 29.20 | 22.23 | 32.18 | |||||||||||||
| 1969 | 21.23 | 19.64 | 24.10 | 31.10 | 40.56 | d | 47.03 | 48.65 | 45.29 | 41.29 | b | 27.00 | a | 20.17 | 24.48 | 32.54 | ||||||||||
| 1970 | 25.39 | 26.43 | 25.94 | 25.03 | 37.29 | 47.63 | 50.74 | 46.16 | 33.80 | 27.67 | a | 29.73 | 17.90 | 32.81 | ||||||||||||
| 1971 | 23.29 | 23.43 | 23.71 | 30.07 | a | 38.70 | a | 43.38 | a | 49.84 | 50.74 | 32.67 | 28.10 | b | 24.93 | 18.39 | 32.27 | |||||||||
| 1972 | 15.58 | 22.69 | 30.13 | 29.40 | 38.90 | 43.00 | a | 47.71 | 46.39 | 31.93 | 28.19 | 25.97 | 11.00 | 30.91 | ||||||||||||
| 1973 | 16.97 | 23.89 | 24.19 | 27.21 | a | 38.73 | a | 42.45 | a | 46.23 | a | 46.33 | d | 39.70 | 29.25 | g | 31.20 | 25.55 | i | 33.69 | ||||||
| 1974 | 18.14 | b | 20.89 | i | 25.41 | d | 30.27 | d | 35.12 | g | 45.65 | m | 45.06 | n | 42.82 | n | 33.95 | k | 27.05 | l | 21.41 | h | 20.94 | m | 24.60 | |
| 1975 | 14.10 | a | 18.52 | g | 24.23 | 25.33 | f | 36.93 | p | 43.04 | f | 53.42 | e | 43.54 | c | 35.00 | f | 31.45 | i | 18.10 | j | 23.95 | i | 33.82 | ||
| 1976 | 20.31 | b | 21.09 | f | 19.82 | c | 27.52 | a | 36.93 | b | 39.00 | f | 49.56 | f | 46.75 | c | 41.93 | a | 26.22 | d | 21.09 | h | 10.31 | e | 28.72 | |
| 1977 | 4.08 | f | 19.88 | c | 21.60 | a | 29.43 | b | 33.75 | c | 47.29 | f | 46.00 | d | 50.06 | m | 38.95 | h | 29.00 | p | 23.28 | e | 24.00 | e | 28.28 | |
| 1978 | 26.54 | r | 24.57 | e | 29.40 | a | 30.73 | 35.39 | 43.39 | b | 49.61 | 46.03 | 38.38 | a | 26.48 | d | 18.50 | 12.24 | b | 32.25 | ||||||
| 1979 | 6.65 | 21.56 | l | 28.43 | a | 31.15 | d | 38.48 | d | 45.00 | h | 49.28 | b | 49.78 | h | 42.65 | j | 35.52 | b | 20.00 | 22.07 | b | 28.95 | |||
| 1980 | 18.48 | b | 26.64 | g | 24.33 | s | 31.96 | d | 38.86 | c | 40.79 | f | 49.45 | 44.28 | b | 39.68 | b | 28.46 | e | 25.85 | c | 18.90 | 32.88 | |||
| 1981 | 23.94 | 20.23 | b | 26.52 | 33.26 | c | 38.39 | 42.13 | 45.90 | 47.81 | 38.60 | 29.42 | e | 26.03 | 23.83 | a | 33.01 | |||||||||
| 1982 | 13.90 | 20.21 | 26.29 | 26.27 | 35.39 | 44.60 | 47.83 | b | 47.74 | 37.17 | 29.65 | 19.63 | 18.19 | 30.57 | ||||||||||||
| 1983 | 22.97 | 26.86 | 30.52 | 29.13 | 38.68 | 43.43 | 47.45 | 50.74 | 38.20 | 33.55 | 29.83 | 17.26 | 34.05 | |||||||||||||
| 1984 | 10.52 | 16.05 | j | 28.29 | 31.33 | 40.42 | 45.17 | 56.32 | 51.30 | a | 39.88 | f | 31.76 | b | 28.64 | b | 13.96 | c | 33.77 | |||||||
| 1985 | 11.34 | b | 15.00 | a | 21.77 | 34.73 | 40.61 | 48.41 | a | 57.97 | 48.35 | 34.87 | 21.83 | m | 5.77 | -5.90 | 28.45 | |||||||||
| 1986 | 15.53 | n | 28.50 | r | 30.95 | l | 27.89 | b | 36.68 | i | 47.21 | a | 46.13 | 51.10 | k | ----- | z | 36.47 | l | 37.11 | u | 15.59 | n | 40.41 | ||
| 1987 | 12.90 | 28.40 | c | 26.74 | 25.47 | m | 33.29 | n | 42.33 | i | 49.81 | 49.61 | 39.25 | n | 33.90 | j | 28.50 | j | 20.85 | k | 33.49 | |||||
| 1988 | 11.33 | v | 19.00 | 24.69 | o | 33.75 | n | 35.58 | l | 49.60 | 50.68 | l | 47.37 | l | 39.53 | 35.64 | i | 27.94 | l | 20.50 | u | 36.04 | ||||
| 1989 | 11.30 | k | ----- | z | 29.06 | o | 34.10 | 38.74 | 47.03 | 50.90 | 48.13 | 41.70 | 30.47 | l | 23.60 | 17.55 | 37.72 | |||||||||
| 1990 | 21.87 | 17.89 | 26.03 | 35.87 | 35.61 | 45.00 | 53.90 | 49.68 | 45.17 | 31.61 | 25.03 | a | 8.35 | 33.00 | ||||||||||||
| 1991 | 15.81 | 25.82 | 25.41 | i | 29.21 | k | 37.06 | 38.06 | n | ----- | z | 49.82 | i | 40.67 | 30.32 | 27.11 | k | 20.94 | 28.44 | |||||||
| 1992 | 20.52 | 26.41 | 27.81 | 33.83 | 39.48 | 46.13 | 47.13 | 47.58 | 38.50 | 31.71 | 23.50 | 16.84 | 33.29 | |||||||||||||
| 1993 | 9.84 | 13.36 | 27.10 | 30.70 | 40.65 | 40.93 | 42.00 | 44.77 | 37.37 | 33.35 | 14.83 | 20.58 | 29.62 | |||||||||||||
| 1994 | 22.19 | 19.75 | 27.13 | 31.87 | 40.71 | 42.83 | 50.68 | 48.03 | 38.80 | 29.23 | 21.53 | 16.71 | 32.46 | |||||||||||||
| 1995 | 25.48 | 26.32 | 27.39 | 29.03 | ----- | z | 42.13 | 47.94 | 42.48 | 38.67 | 28.55 | 30.40 | 23.97 | 32.94 | ||||||||||||
| 1996 | 23.03 | 22.31 | 28.29 | 31.40 | 36.81 | 43.53 | 49.77 | 46.00 | 37.17 | 31.42 | 26.50 | 25.90 | 33.51 | |||||||||||||
| 1997 | 20.74 | 24.39 | 27.32 | 32.47 | 42.06 | 43.70 | 47.23 | 48.45 | 41.40 | 30.90 | 25.40 | ----- | z | 34.92 | ||||||||||||
| 1998 | 24.87 | 23.75 | 27.58 | 30.63 | 36.89 | v | 42.27 | 53.29 | 46.23 | 44.33 | 29.53 | l | 28.83 | 16.87 | 33.87 | |||||||||||
| 1999 | 21.15 | e | 21.23 | b | 27.13 | 27.73 | o | 36.05 | i | 42.21 | p | 49.59 | n | 47.71 | g | 35.65 | d | 27.60 | p | 27.81 | i | 19.94 | n | 26.29 | ||
| 2000 | 21.71 | j | 27.53 | l | 26.63 | l | 33.60 | j | 39.96 | c | 44.44 | l | 46.21 | q | 48.57 | q | 34.77 | q | 30.25 | w | 17.61 | l | 20.30 | h | 39.96 | |
| 2001 | 14.47 | l | 12.00 | p | 28.58 | l | 30.47 | k | 38.74 | l | 43.00 | e | 49.11 | d | 48.33 | g | 37.07 | p | 34.00 | y | 26.11 | k | 22.11 | m | 46.06 | |
| 2002 | 21.20 | p | 19.73 | q | 22.30 | k | 33.55 | s | 35.90 | k | 40.00 | v | 53.17 | h | 40.69 | r | 39.50 | v | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 2003 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 40.67 | x | 55.43 | j | 49.80 | k | 41.00 | k | 33.50 | k | 18.21 | p | 23.93 | q | 9999.00 | |
| 2004 | 15.45 | t | 18.18 | l | 29.07 | q | 30.53 | m | 35.86 | q | 42.53 | m | 51.67 | s | 53.12 | w | 40.00 | m | 31.25 | o | 24.07 | o | 22.82 | n | 9999.00 | |
| 2005 | 20.08 | s | 15.21 | n | 27.00 | m | 32.50 | v | 38.81 | o | 41.33 | r | 52.00 | p | ----- | z | 38.50 | r | 31.08 | r | 21.25 | n | 5.54 | r | 9999.00 | |
| 2006 | 22.79 | q | 17.64 | n | 26.06 | n | 29.33 | r | 38.18 | n | 48.67 | r | 54.60 | u | 46.47 | l | ----- | z | 29.11 | m | 25.60 | o | 16.00 | q | 9999.00 | |
| 2007 | 11.82 | n | 20.88 | l | 27.32 | l | 24.43 | w | 36.46 | r | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 2008 | 12.16 | 22.59 | 24.23 | 24.93 | 38.19 | 43.47 | 50.94 | m | 49.68 | 40.23 | 33.13 | 26.97 | 15.74 | 30.12 | ||||||||||||
| 2009 | 19.74 | 21.90 | r | 24.73 | e | 28.70 | 39.29 | 45.97 | 52.13 | 49.45 | 42.73 | 29.81 | 20.43 | 12.84 | 33.26 | |||||||||||
| 2010 | 26.58 | 24.71 | 24.26 | 29.23 | 33.87 | 44.33 | 49.13 | 48.19 | 41.33 | 36.81 | 23.90 | 21.81 | 33.68 | |||||||||||||
| 2011 | 18.68 | 18.44 | j | 28.23 | 29.23 | 36.19 | 44.00 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 31.27 | ||||||
| 2012 | 20.40 | z | 21.86 | 27.77 | 34.10 | 38.39 | 42.57 | 53.45 | 50.90 | 43.17 | 32.23 | 27.73 | 21.00 | 35.74 | ||||||||||||
| 2013 | 10.10 | 21.54 | 27.32 | 37.00 | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 19.65 | ||||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 18.07 | 22.77 | 26.05 | 30.15 | 37.74 | 44.38 | 49.35 | 47.30 | 39.09 | 30.46 | 24.45 | 17.70 | 32.43 | |||||||||||||
| S.D. | 5.42 | 3.77 | 2.33 | 2.73 | 2.13 | 2.05 | 3.25 | 2.24 | 3.22 | 2.49 | 5.00 | 5.96 | 1.10 | |||||||||||||
| SKEW | -0.41 | -0.26 | -0.42 | 0.00 | -0.03 | 0.67 | 0.35 | 0.05 | -0.25 | 0.56 | -1.52 | -1.71 | -0.97 | |||||||||||||
| MAX | 26.58 | 30.46 | 30.52 | 35.87 | 42.06 | 49.60 | 57.97 | 51.30 | 45.17 | 36.81 | 31.20 | 25.90 | 34.05 | |||||||||||||
| MIN | 6.65 | 13.36 | 19.82 | 24.93 | 33.75 | 40.93 | 42.00 | 42.48 | 31.93 | 26.22 | 5.77 | -5.90 | 29.62 | |||||||||||||
| NO YRS | 40 | 36 | 41 | 41 | 39 | 38 | 40 | 38 | 37 | 33 | 37 | 37 | 21 | |||||||||||||