| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1978 | ----- | z | ----- | z | ----- | z | 34.64 | e | 41.19 | d | 50.47 | 54.19 | 52.13 | 41.97 | a | 36.35 | 26.70 | 13.52 | b | 39.02 | c | |||||
| 1979 | 9.23 | 10.18 | 29.03 | b | 34.40 | 41.81 | 46.60 | 53.26 | 53.61 | 48.23 | 38.58 | 23.07 | a | 16.74 | 33.73 | |||||||||||
| 1980 | 24.83 | a | 27.97 | 27.45 | 35.03 | 41.20 | a | 48.13 | 57.00 | 53.35 | 45.69 | a | 35.16 | 25.27 | 19.41 | b | 36.71 | |||||||||
| 1981 | 20.35 | 18.39 | 28.87 | 38.50 | 43.82 | c | 55.80 | 55.42 | 54.76 | b | 48.40 | 35.77 | a | 28.44 | c | 22.57 | a | 37.59 | ||||||||
| 1982 | 15.26 | 22.96 | c | 28.57 | a | 31.71 | b | 42.80 | a | 50.00 | 55.33 | a | 56.29 | 46.86 | b | 33.71 | 26.64 | b | 23.19 | 36.11 | ||||||
| 1983 | 19.41 | d | 27.30 | a | 33.45 | 33.20 | 41.45 | b | 50.85 | c | 55.94 | 57.42 | 49.00 | b | 37.72 | b | 25.69 | d | 25.67 | a | 38.09 | |||||
| 1984 | 20.59 | b | 22.12 | c | 26.67 | a | 30.68 | b | 47.00 | a | 50.17 | 60.48 | 57.14 | b | 49.03 | a | 32.38 | b | 24.86 | b | 13.88 | f | 38.28 | a | ||
| 1985 | 0.28 | b | 4.64 | 29.04 | d | 37.59 | a | 44.52 | 54.17 | 58.37 | a | 52.67 | a | 44.96 | d | 35.76 | b | 18.55 | a | 20.90 | 33.45 | |||||
| 1986 | 25.45 | b | 30.56 | a | 34.22 | d | 36.73 | 42.61 | 53.93 | b | 54.43 | a | 57.43 | c | 44.55 | a | 34.39 | c | 25.43 | 15.28 | b | 37.92 | ||||
| 1987 | 10.23 | 23.56 | a | 28.52 | d | 35.36 | e | 45.36 | c | 53.83 | 54.87 | a | 54.43 | a | 48.32 | b | 39.45 | 29.56 | c | 18.46 | c | 36.83 | ||||
| 1988 | 2.89 | c | 9.97 | 27.72 | b | 35.89 | b | 40.96 | c | 53.30 | c | 58.58 | 55.90 | a | 45.97 | 39.81 | 28.82 | b | 13.16 | 34.41 | ||||||
| 1989 | -2.61 | 14.40 | c | 33.68 | 39.14 | a | 44.19 | 50.50 | 57.90 | 51.90 | 45.59 | a | 33.56 | d | 22.10 | a | 13.45 | 33.65 | ||||||||
| 1990 | 15.36 | c | 18.08 | b | 31.39 | 37.57 | b | 42.84 | 51.53 | 60.26 | 55.55 | 49.45 | a | 36.44 | d | 23.62 | a | 9.50 | a | 35.97 | ||||||
| 1991 | 14.81 | 22.00 | a | 27.35 | 31.97 | 41.13 | 52.00 | 59.52 | 56.03 | a | 47.14 | b | 38.16 | 25.59 | a | 15.03 | 35.89 | |||||||||
| 1992 | 10.68 | c | 28.86 | 34.80 | a | 38.53 | 47.80 | a | 51.07 | 57.53 | a | 57.61 | 47.40 | 40.32 | 20.70 | 14.16 | 37.46 | |||||||||
| 1993 | 15.25 | c | 25.14 | 34.43 | a | 36.70 | 46.65 | 49.17 | a | 54.42 | 55.03 | a | 44.83 | 37.32 | 21.17 | 14.26 | 36.20 | |||||||||
| 1994 | 17.37 | a | 22.14 | 31.40 | a | 35.93 | 44.50 | a | 53.20 | 59.32 | 56.40 | a | 45.73 | 36.10 | 18.85 | d | 16.57 | a | 36.46 | |||||||
| 1995 | 27.83 | a | 29.07 | a | 30.93 | b | 33.48 | a | 42.48 | 49.04 | b | 56.62 | b | 55.84 | 47.66 | a | 34.81 | 25.90 | a | 19.87 | 37.79 | |||||
| 1996 | 19.58 | 25.93 | 28.87 | a | 35.73 | 45.37 | a | 54.07 | a | 60.06 | 56.87 | 45.53 | 34.68 | 27.20 | 23.70 | a | 38.13 | |||||||||
| 1997 | 21.16 | 26.37 | a | 29.29 | 34.24 | a | 45.55 | 53.97 | 56.97 | 55.84 | 51.47 | 33.84 | 27.86 | b | 19.16 | 37.98 | ||||||||||
| 1998 | 23.87 | 28.61 | 30.14 | b | 34.07 | 39.47 | a | 48.34 | a | 59.00 | 59.00 | 51.41 | a | 35.25 | c | 28.33 | 17.94 | 37.95 | ||||||||
| 1999 | 19.68 | 23.89 | 29.30 | a | 33.57 | b | 43.55 | 50.90 | 60.08 | g | 55.45 | 47.21 | a | 33.34 | b | ----- | z | 14.67 | a | 35.16 | b | |||||
| 2000 | 23.28 | f | 28.90 | 30.68 | 38.93 | a | 46.35 | 53.48 | a | 54.87 | 56.52 | 46.21 | a | 37.83 | a | 21.77 | 18.73 | a | 39.48 | a | ||||||
| 2001 | 18.26 | 23.19 | b | 32.37 | a | 34.50 | 46.77 | 52.83 | 55.52 | 56.93 | a | 48.97 | 38.43 | a | 28.90 | a | 16.39 | c | 37.76 | |||||||
| 2002 | 20.07 | a | 21.43 | 24.53 | a | 37.47 | 42.33 | a | 52.53 | 60.23 | 54.61 | 48.03 | 33.20 | a | 22.76 | a | 18.00 | c | 36.27 | |||||||
| 2003 | 22.29 | 22.04 | a | 29.73 | a | 34.85 | c | 44.90 | b | 54.34 | a | 60.29 | 58.00 | a | 49.47 | 39.63 | a | 24.61 | b | 15.78 | h | 40.01 | a | |||
| 2004 | 5.56 | f | 22.79 | a | 34.45 | 38.57 | b | 44.33 | a | 54.29 | b | 57.42 | 55.33 | a | 45.67 | 39.03 | a | 28.48 | c | 20.13 | a | 40.05 | a | |||
| 2005 | 26.00 | 29.70 | a | 30.50 | a | 34.47 | 46.48 | 50.11 | b | 60.45 | b | 56.87 | 44.65 | j | 37.61 | 26.50 | b | 18.81 | 37.95 | a | ||||||
| 2006 | 21.47 | a | 19.89 | a | 25.30 | a | 38.03 | 47.87 | a | 57.15 | c | 61.65 | 53.19 | 46.31 | a | 35.23 | 22.47 | 13.03 | 36.80 | |||||||
| 2007 | 6.87 | a | 22.55 | h | 30.39 | 38.65 | g | 43.33 | d | 52.23 | 61.74 | 58.52 | 48.13 | 35.03 | 25.00 | 17.70 | a | 37.89 | b | |||||||
| 2008 | 18.48 | 23.25 | a | 28.23 | a | 31.16 | k | 36.10 | j | 44.00 | m | 58.43 | c | 56.68 | 47.77 | 34.06 | 29.90 | 13.65 | 34.49 | c | ||||||
| 2009 | 13.03 | 23.64 | 28.42 | 34.03 | a | 48.85 | e | 52.03 | 59.48 | 54.19 | 50.83 | 35.45 | 23.33 | 9.39 | 36.06 | |||||||||||
| 2010 | 8.10 | 24.68 | 28.74 | 33.73 | 39.08 | g | 53.70 | c | 59.53 | a | 55.97 | b | 44.90 | 41.19 | 26.23 | 27.24 | b | 36.73 | a | |||||||
| 2011 | 19.52 | 21.11 | a | 29.81 | 34.48 | a | 40.79 | b | 51.34 | a | 57.00 | a | 56.20 | a | 48.96 | e | 37.26 | 22.18 | b | 14.65 | 36.11 | |||||
| 2012 | 16.45 | 23.45 | 30.48 | 37.27 | 45.03 | a | 51.47 | 55.61 | 59.48 | 48.62 | a | 37.64 | c | 29.21 | f | 13.61 | h | 40.55 | b | |||||||
| 2013 | -1.10 | 23.18 | 33.41 | b | 36.73 | 44.42 | 55.97 | a | 62.06 | 55.00 | 51.24 | a | 32.94 | 26.63 | 4.87 | 35.45 | ||||||||||
| 2014 | 11.03 | 26.32 | 30.84 | 37.47 | 44.87 | 54.33 | 62.90 | 56.13 | 53.07 | 39.97 | 28.32 | h | 24.59 | b | 40.14 | a | ||||||||||
| 2015 | 23.55 | 27.89 | 32.74 | 35.40 | 45.77 | 56.60 | 57.77 | 57.32 | 50.73 | 42.48 | 22.47 | 17.90 | 39.22 | |||||||||||||
| 2016 | 15.16 | 11.14 | 33.87 | 39.50 | 44.71 | 58.43 | 58.61 | 55.32 | 46.53 | 39.84 | 25.90 | 17.10 | 37.18 | |||||||||||||
| 2017 | 19.23 | 29.71 | 33.52 | 38.07 | 46.55 | 56.80 | 62.74 | 60.10 | 49.00 | 34.52 | 28.67 | 15.29 | 39.52 | |||||||||||||
| 2018 | 20.61 | 21.14 | 29.07 | b | 40.37 | 47.13 | 55.00 | 63.55 | 59.06 | 49.10 | 42.32 | i | 25.80 | y | 20.77 | 40.58 | b | |||||||||
| 2019 | 22.29 | 21.36 | 32.97 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 25.54 | i | |||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 16.23 | 22.67 | 30.37 | 35.86 | 44.28 | 52.59 | 58.23 | 56.00 | 47.75 | 36.61 | 25.14 | 17.25 | 36.67 | |||||||||||||
| S.D. | 7.54 | 5.87 | 2.58 | 2.31 | 2.30 | 2.66 | 2.67 | 1.92 | 2.29 | 2.55 | 2.96 | 4.60 | 1.55 | |||||||||||||
| SKEW | -0.91 | -1.22 | -0.02 | -0.11 | -0.10 | 0.00 | 0.08 | -0.10 | 0.03 | 0.32 | -0.39 | -0.14 | -0.45 | |||||||||||||
| MAX | 27.83 | 30.56 | 34.80 | 40.37 | 48.85 | 58.43 | 63.55 | 60.10 | 53.07 | 42.48 | 29.90 | 27.24 | 39.52 | |||||||||||||
| MIN | -2.61 | 4.64 | 24.53 | 30.68 | 39.47 | 46.60 | 53.26 | 51.90 | 41.97 | 32.38 | 18.55 | 4.87 | 33.45 | |||||||||||||
| YRS | 39 | 40 | 41 | 39 | 39 | 40 | 40 | 41 | 40 | 40 | 37 | 38 | 28 | |||||||||||||