| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1968 | 21.90 | 29.28 | 30.39 | 26.73 | 33.45 | 37.40 | 45.42 | 43.39 | 41.70 | 32.65 | 29.73 | 19.00 | 32.59 | |||||||||||||
| 1969 | 11.10 | 19.50 | 26.84 | 31.37 | 38.29 | 47.07 | 43.74 | 43.32 | 42.97 | 31.81 | 28.63 | 24.77 | 32.45 | |||||||||||||
| 1970 | 23.00 | 29.04 | 27.87 | 27.93 | 35.16 | 47.40 | 47.32 | 46.32 | 38.10 | 34.23 | 30.30 | 22.55 | 34.10 | |||||||||||||
| 1971 | 25.13 | 26.71 | 26.58 | 30.33 | 38.65 | 39.13 | 48.74 | 49.52 | 38.93 | 33.81 | 29.23 | 23.06 | 34.15 | |||||||||||||
| 1972 | 21.26 | 26.34 | 30.19 | 28.00 | 38.68 | 44.07 | 48.68 | 49.83 | a | 39.07 | 33.06 | 32.77 | 18.10 | 34.17 | ||||||||||||
| 1973 | 19.68 | 26.36 | 27.19 | 27.83 | 35.68 | 40.00 | 42.94 | 38.39 | 40.37 | 32.35 | 26.73 | 28.26 | 32.15 | |||||||||||||
| 1974 | 16.52 | 26.86 | 27.19 | 32.29 | b | 34.03 | 41.13 | 43.23 | 43.00 | 38.83 | 31.10 | 29.70 | 24.97 | 32.40 | ||||||||||||
| 1975 | 21.77 | 21.89 | 25.23 | 25.47 | 33.29 | 37.60 | 47.52 | 41.65 | 38.68 | b | 33.71 | 27.47 | 25.29 | 31.63 | ||||||||||||
| 1976 | 23.73 | a | 22.21 | 23.45 | 30.07 | 33.06 | 36.20 | 43.45 | 43.42 | 42.67 | 30.13 | 29.47 | 21.77 | 31.64 | ||||||||||||
| 1977 | 17.58 | 26.00 | 25.87 | 30.10 | 32.55 | 42.03 | 41.84 | 49.35 | 37.53 | 32.23 | 26.17 | 25.23 | 32.21 | |||||||||||||
| 1978 | 24.97 | 27.79 | 29.10 | 32.20 | 31.65 | 40.90 | 44.32 | 46.52 | 39.55 | a | 30.94 | 19.33 | 13.55 | 31.73 | ||||||||||||
| 1979 | 5.68 | 24.11 | 27.39 | 28.80 | 33.77 | 38.67 | 43.58 | 43.94 | 41.86 | a | 35.07 | b | 24.07 | 25.23 | 31.01 | |||||||||||
| 1980 | 14.45 | 27.00 | b | 25.90 | b | 33.14 | a | 35.73 | a | 38.69 | a | 44.61 | 39.77 | 40.43 | 31.37 | a | 29.20 | 27.00 | 32.27 | |||||||
| 1981 | 28.52 | 25.85 | a | 28.10 | 31.30 | 34.90 | 40.37 | 40.74 | 45.75 | c | 38.07 | a | 29.55 | b | 26.76 | a | 22.13 | a | 32.67 | |||||||
| 1982 | 17.97 | 20.86 | 24.68 | 25.47 | 31.00 | 41.57 | 41.65 | 44.10 | 40.80 | 33.23 | 24.00 | 21.32 | 30.55 | |||||||||||||
| 1983 | 28.03 | 29.86 | 32.35 | 28.87 | 34.52 | 37.87 | 42.39 | 42.87 | 33.00 | 30.77 | 31.57 | 15.19 | 32.27 | |||||||||||||
| 1984 | 22.90 | 27.10 | 30.23 | 29.00 | 33.94 | 38.23 | 41.61 | 40.90 | 36.60 | 27.65 | 26.33 | 16.35 | 30.90 | |||||||||||||
| 1985 | 15.81 | 17.25 | ----- | z | 28.70 | 32.26 | 37.10 | 42.58 | 35.50 | a | 31.90 | 27.65 | 15.20 | 9.65 | 26.69 | |||||||||||
| 1986 | 23.32 | 24.39 | 29.43 | a | 24.80 | 32.58 | 40.47 | 39.58 | 45.97 | 35.80 | 33.77 | 28.00 | 21.48 | 31.63 | ||||||||||||
| 1987 | 20.19 | 25.75 | 28.71 | 32.87 | 37.65 | 40.07 | 41.50 | q | 36.82 | t | 33.60 | y | ----- | z | 23.46 | q | 15.93 | p | 30.87 | |||||||
| 1988 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 42.17 | a | 47.45 | 44.68 | 40.77 | 41.16 | 28.84 | k | ----- | z | 43.25 | |||||
| 1989 | ----- | z | 14.09 | q | ----- | z | 35.33 | 36.45 | k | 44.40 | 43.53 | a | 44.94 | 41.50 | 34.61 | 32.62 | q | 22.88 | n | 40.72 | ||||||
| 1990 | ----- | z | 17.36 | q | 29.29 | 34.50 | 34.50 | a | 44.00 | d | 52.35 | 49.26 | 46.53 | 33.32 | 26.80 | t | 13.83 | s | 40.47 | |||||||
| 1991 | ----- | z | ----- | z | 26.06 | 30.77 | 35.13 | 37.77 | 48.42 | 50.36 | i | 44.03 | 34.45 | ----- | z | 25.71 | x | 36.66 | ||||||||
| 1992 | 23.00 | w | 28.38 | u | 32.78 | m | 37.32 | k | 37.94 | m | ----- | z | 47.73 | a | 47.33 | a | 40.12 | m | 36.29 | x | ----- | z | ----- | z | 47.53 | |
| 1993 | 14.00 | z | 17.50 | z | 31.00 | p | 32.73 | 41.42 | s | 41.59 | m | 41.05 | k | 42.07 | q | 40.90 | a | 36.39 | 17.69 | q | 24.19 | o | 36.67 | |||
| 1994 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| 1995 | 25.23 | 28.86 | 28.77 | 31.33 | 38.45 | 43.40 | 47.58 | 43.29 | 46.13 | 34.45 | 33.53 | 24.81 | 35.49 | |||||||||||||
| 1996 | 22.55 | 21.11 | j | 28.55 | 34.43 | 33.94 | 40.57 | 49.45 | 48.09 | i | 38.97 | 35.26 | 28.55 | j | 22.81 | 34.06 | ||||||||||
| 1997 | 23.55 | 26.04 | 30.23 | 30.97 | 40.77 | ----- | z | 48.43 | a | 50.48 | 46.70 | ----- | z | 31.20 | 24.16 | 35.25 | ||||||||||
| 1998 | 25.32 | 29.18 | 30.71 | 32.10 | 38.53 | a | 42.67 | 51.97 | 49.00 | 46.27 | 33.32 | 32.43 | 23.03 | a | 36.21 | |||||||||||
| 1999 | 28.23 | i | 27.56 | j | 28.45 | k | ----- | z | 33.14 | b | 39.23 | d | 45.68 | c | 50.52 | b | 41.30 | c | 33.45 | i | 32.40 | j | 28.70 | k | 41.97 | |
| 2000 | 21.91 | i | 24.95 | j | 28.33 | d | 34.14 | b | 37.42 | e | 44.00 | b | 45.45 | b | 44.37 | a | 40.44 | e | 34.29 | j | 22.70 | g | 22.17 | g | 39.16 | |
| 2001 | 23.27 | p | 20.00 | p | 27.76 | j | 30.81 | d | 37.26 | d | 41.44 | e | 45.97 | b | 49.40 | a | 44.65 | d | 32.96 | h | 32.17 | g | 24.69 | b | 39.17 | |
| 2002 | 24.97 | 25.18 | 26.68 | 32.00 | 36.81 | 44.87 | 48.35 | 45.58 | 43.27 | 32.10 | 29.70 | 27.16 | 34.72 | |||||||||||||
| 2003 | 25.88 | w | 26.22 | j | 32.81 | 32.70 | 38.58 | 41.83 | 48.35 | 49.55 | 46.13 | 39.38 | g | 25.60 | 25.68 | i | 39.44 | |||||||||
| 2004 | 20.16 | f | 26.24 | 32.06 | 34.20 | 39.19 | 44.50 | 50.03 | 52.48 | 41.97 | 36.87 | 29.25 | f | 27.84 | 38.54 | |||||||||||
| 2005 | 23.16 | 25.50 | 31.45 | 33.96 | e | 41.06 | 41.23 | 47.32 | 48.32 | 40.17 | 36.16 | 27.70 | 18.54 | c | 34.55 | |||||||||||
| 2006 | 29.90 | 24.18 | 28.58 | 34.27 | 39.61 | 43.70 | 50.10 | 46.52 | 41.73 | 33.13 | ----- | z | 20.50 | c | 35.66 | |||||||||||
| 2007 | 17.87 | 26.68 | 30.77 | 31.07 | 37.65 | ----- | z | 50.16 | 45.87 | 39.83 | 33.23 | 26.40 | 22.58 | 32.92 | ||||||||||||
| 2008 | 18.10 | 25.24 | 25.03 | 26.20 | 41.35 | 38.97 | 47.94 | 48.42 | 38.71 | f | 33.00 | 31.70 | 17.90 | 32.17 | ||||||||||||
| 2009 | 21.55 | 24.71 | 23.74 | 31.97 | 38.29 | 44.40 | 50.55 | 47.52 | 42.53 | 31.94 | 28.67 | 18.45 | 33.69 | |||||||||||||
| 2010 | 29.68 | 29.36 | 29.26 | 31.17 | 35.29 | 41.70 | 46.35 | 45.55 | 43.60 | 36.39 | 26.10 | 24.27 | e | 34.89 | ||||||||||||
| 2011 | 25.22 | h | 21.12 | d | 28.90 | 28.07 | c | 34.46 | c | 40.04 | d | 44.93 | c | 45.50 | e | 45.37 | c | 37.00 | a | 25.62 | n | 21.88 | f | 36.16 | ||
| 2012 | 20.65 | n | 26.73 | g | 27.17 | g | 35.09 | g | 35.55 | b | 42.11 | b | 47.60 | a | 48.13 | a | 42.54 | d | 33.00 | z | 34.43 | w | 28.07 | q | 43.19 | |
| 2013 | 18.71 | q | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 9999.00 | |
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 21.46 | 25.51 | 28.28 | 30.70 | 35.95 | 41.22 | 46.18 | 45.76 | 41.03 | 33.27 | 27.85 | 21.93 | 32.92 | |||||||||||||
| S.D. | 5.29 | 2.99 | 2.38 | 2.76 | 2.74 | 2.73 | 3.17 | 3.56 | 3.40 | 2.65 | 3.88 | 4.30 | 1.54 | |||||||||||||
| SKEW | -0.87 | -0.87 | -0.12 | -0.40 | 0.21 | 0.26 | -0.11 | -0.61 | -0.45 | 0.31 | -1.37 | -0.90 | 0.46 | |||||||||||||
| MAX | 29.90 | 29.86 | 32.81 | 35.33 | 41.35 | 47.40 | 52.35 | 52.48 | 46.70 | 41.16 | 33.53 | 28.26 | 36.21 | |||||||||||||
| MIN | 5.68 | 17.25 | 23.45 | 24.80 | 31.00 | 36.20 | 39.58 | 35.50 | 31.90 | 27.65 | 15.20 | 9.65 | 30.55 | |||||||||||||
| NO YRS | 31 | 32 | 36 | 40 | 40 | 40 | 42 | 40 | 41 | 36 | 29 | 32 | 24 | |||||||||||||