| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1975 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1976 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1977 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1978 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1979 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1980 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1981 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1982 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1983 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1984 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1985 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1986 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1987 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1988 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1989 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1990 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1991 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1992 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1993 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1994 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1995 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1996 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1997 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1998 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1999 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2000 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2001 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2002 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2003 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 37.80 | a | 37.80 | k |
| 2004 | 32.74 | 32.62 | 55.19 | 56.33 | 66.55 | 75.93 | 81.29 | 77.87 | a | 70.63 | 54.90 | 42.53 | 34.24 | b | 56.74 | |||||||||||
| 2005 | 39.10 | a | ----- | z | 43.90 | a | 53.33 | 62.87 | 69.80 | 84.45 | 77.97 | 70.90 | 58.84 | 46.17 | 34.81 | 58.38 | a | |||||||||
| 2006 | 34.81 | 36.11 | 40.58 | 56.30 | 67.78 | h | 78.41 | c | 83.77 | a | 78.77 | 68.83 | 54.90 | 44.93 | 32.97 | 55.49 | a | |||||||||
| 2007 | 29.16 | 37.79 | 51.06 | 56.03 | a | 66.00 | 79.34 | a | 85.71 | 82.45 | 70.87 | 57.48 | 51.57 | 27.45 | 57.91 | |||||||||||
| 2008 | 27.90 | 33.72 | 39.16 | ----- | z | ----- | z | 72.80 | 82.94 | 80.26 | 71.27 | 58.90 | 47.80 | 33.58 | 54.83 | b | ||||||||||
| 2009 | 34.68 | 38.46 | 44.39 | 51.43 | 64.74 | 69.07 | 81.97 | 79.42 | 73.00 | 51.90 | a | 47.80 | 26.87 | 55.31 | ||||||||||||
| 2010 | 34.26 | 33.82 | 42.58 | 51.40 | 58.53 | a | 72.30 | 81.68 | 78.23 | 75.27 | 58.17 | a | 38.70 | 36.68 | 55.13 | |||||||||||
| 2011 | 29.68 | 31.86 | ----- | z | 48.90 | 57.65 | 72.59 | a | 80.39 | 80.77 | 71.80 | 57.03 | 42.10 | 33.06 | 55.07 | a | ||||||||||
| 2012 | 39.35 | 35.38 | 49.48 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 41.41 | i | |||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 33.52 | 34.97 | 45.79 | 53.39 | 62.72 | 73.78 | 82.77 | 79.47 | 71.57 | 56.52 | 45.20 | 33.05 | 56.27 | |||||||||||||
| S.D. | 4.10 | 2.38 | 5.57 | 2.95 | 3.82 | 3.77 | 1.78 | 1.61 | 1.90 | 2.44 | 4.04 | 3.71 | 1.31 | |||||||||||||
| SKEW | 0.11 | 0.23 | 0.49 | -0.26 | -0.41 | 0.31 | 0.33 | 0.72 | 0.70 | -0.79 | -0.07 | -0.65 | 0.37 | |||||||||||||
| MAX | 39.35 | 38.46 | 55.19 | 56.33 | 66.55 | 79.34 | 85.71 | 82.45 | 75.27 | 58.90 | 51.57 | 37.80 | 57.91 | |||||||||||||
| MIN | 27.90 | 31.86 | 39.16 | 48.90 | 57.65 | 69.07 | 80.39 | 77.87 | 68.83 | 51.90 | 38.70 | 26.87 | 55.13 | |||||||||||||
| YRS | 9 | 8 | 8 | 7 | 6 | 8 | 8 | 8 | 8 | 8 | 8 | 9 | 4 | |||||||||||||