| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1974 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 69.39 | 62.45 | a | 49.97 | 40.10 | a | 30.40 | a | 50.46 | g | ||
| 1975 | 32.05 | a | 35.77 | 40.23 | 41.63 | 55.11 | 63.22 | 73.40 | 66.71 | 64.07 | 48.84 | 37.71 | b | 34.12 | a | 49.40 | ||||||||||
| 1976 | 32.06 | 37.43 | a | 39.52 | 46.37 | 60.24 | 63.95 | 71.65 | 64.02 | 62.13 | 49.92 | 41.57 | 28.15 | 49.75 | ||||||||||||
| 1977 | 30.29 | b | 38.61 | a | 38.77 | 51.73 | 50.27 | 70.30 | 71.32 | a | 71.45 | 60.95 | 52.13 | a | 42.02 | d | 38.18 | 51.34 | ||||||||
| 1978 | 36.45 | 38.05 | 46.98 | a | 47.43 | c | 53.89 | 62.95 | a | 71.26 | 67.84 | 57.63 | c | 51.79 | 35.60 | a | 24.21 | c | 49.51 | |||||||
| 1979 | 28.21 | c | 35.82 | 42.91 | b | 47.35 | f | 59.07 | a | 64.00 | e | 71.97 | b | 68.28 | d | 63.50 | 53.10 | b | 36.87 | 33.56 | e | 50.66 | a | |||
| 1980 | 36.46 | f | 40.84 | 40.14 | i | 49.75 | 55.56 | m | 64.39 | k | 71.72 | a | 65.60 | b | 58.12 | b | 47.66 | 38.90 | e | 32.75 | i | 53.23 | e | |||
| 1981 | 32.57 | c | 39.22 | a | 42.50 | a | 50.83 | 56.74 | 65.58 | d | ----- | z | 65.23 | a | 63.97 | 47.61 | 43.58 | j | 39.94 | 50.42 | b | |||||
| 1982 | 27.16 | c | 39.48 | a | 39.52 | b | 45.91 | a | 57.94 | 65.45 | 71.29 | 69.57 | h | 59.52 | h | 49.73 | a | 38.38 | b | 33.54 | e | 46.84 | b | |||
| 1983 | 33.96 | g | 40.64 | g | 42.91 | c | 44.36 | a | 56.32 | a | 64.52 | 67.79 | 69.52 | b | 62.48 | e | 49.92 | l | 38.92 | r | 36.20 | h | 58.27 | e | ||
| 1984 | 30.18 | c | 33.80 | f | 42.15 | h | 45.67 | d | 58.93 | c | 62.72 | e | 75.20 | a | 71.94 | d | 64.08 | e | 44.21 | j | 38.64 | i | 28.84 | f | 58.39 | e |
| 1985 | 26.68 | i | 32.71 | i | 37.33 | e | 52.38 | 57.26 | b | 69.93 | a | 74.48 | g | 67.17 | d | 55.48 | b | 46.56 | m | 32.00 | m | 27.90 | g | 56.59 | f | |
| 1986 | 36.41 | d | 40.58 | b | 46.77 | c | 49.94 | c | 57.55 | a | 68.81 | a | 70.45 | l | 73.35 | d | 56.04 | f | 48.38 | o | 40.88 | i | 32.77 | 50.77 | d | |
| 1987 | 29.03 | a | 37.23 | 44.20 | d | 51.71 | a | 59.94 | g | 67.91 | c | 69.67 | b | 73.03 | 64.50 | d | 54.62 | b | 40.57 | b | 30.47 | a | 51.18 | a | ||
| 1988 | 31.19 | d | 36.50 | 42.94 | d | 51.40 | e | 57.09 | c | 72.33 | c | 78.12 | r | 74.38 | c | 63.34 | b | 57.68 | c | 42.38 | b | 30.15 | a | 50.85 | a | |
| 1989 | 28.33 | e | 31.00 | g | 46.58 | f | 54.46 | c | 56.89 | c | 68.31 | c | 74.70 | d | 67.67 | d | 62.62 | a | 51.56 | e | 39.63 | c | 31.43 | a | 53.56 | b |
| 1990 | 29.67 | g | 31.54 | 45.66 | 54.71 | i | 55.70 | a | 67.55 | b | 74.46 | d | 72.52 | a | 67.32 | e | 53.95 | 38.85 | 21.28 | b | 52.88 | b | ||||
| 1991 | 28.04 | c | 41.80 | 40.88 | c | 47.50 | c | 52.40 | b | 62.38 | 75.05 | 73.33 | h | 64.67 | 55.19 | 41.78 | c | 31.45 | a | 49.19 | a | |||||
| 1992 | 31.31 | 41.59 | b | 46.72 | a | 56.12 | f | 64.45 | c | 66.37 | c | 72.50 | 73.00 | b | 64.40 | a | 54.95 | 37.00 | e | 29.34 | b | 52.88 | a | |||
| 1993 | 26.52 | 35.75 | d | 49.39 | 50.56 | f | 60.32 | 61.47 | a | 68.82 | a | 68.78 | a | 62.82 | 53.02 | e | 34.58 | 32.18 | 50.33 | a | ||||||
| 1994 | 33.32 | 35.46 | b | 46.62 | a | 53.38 | e | 59.95 | 68.23 | b | 77.08 | 72.48 | 63.27 | f | 49.86 | c | 33.00 | a | 33.20 | c | 51.14 | a | ||||
| 1995 | 37.85 | a | 44.21 | 43.13 | 48.50 | e | 54.33 | e | 62.04 | c | 71.31 | 71.32 | 65.22 | 52.48 | a | 46.37 | 37.98 | 52.89 | ||||||||
| 1996 | 37.71 | 41.34 | 44.11 | 50.47 | 58.22 | d | 66.82 | 76.34 | 72.42 | 60.77 | 51.27 | 41.05 | b | 38.00 | c | 53.21 | ||||||||||
| 1997 | 34.82 | a | 38.32 | 47.30 | d | 49.92 | e | 62.22 | b | 64.62 | 71.84 | 72.73 | 64.67 | 50.88 | f | 42.10 | a | 29.23 | 52.52 | a | ||||||
| 1998 | 38.74 | 38.20 | a | 43.53 | 46.86 | b | 51.36 | b | 62.72 | 75.03 | 73.65 | 65.15 | 48.53 | b | 40.84 | e | 29.32 | a | 51.16 | |||||||
| 1999 | 35.72 | d | 40.19 | b | 42.72 | b | 48.21 | d | 57.39 | c | 66.00 | 73.35 | 71.24 | d | 63.58 | 53.57 | i | 44.52 | 32.02 | 52.27 | a | |||||
| 2000 | 37.63 | 42.13 | b | 44.29 | 53.03 | 59.81 | 70.25 | 75.31 | ----- | z | 62.41 | a | 51.27 | a | 35.50 | c | 35.00 | i | 53.16 | b | ||||||
| 2001 | 29.21 | x | 34.36 | 47.27 | 49.03 | a | 63.73 | c | ----- | z | 73.38 | s | ----- | z | ----- | z | 52.80 | h | 42.88 | a | 35.50 | a | 45.46 | f | ||
| 2002 | 32.34 | c | 37.82 | c | 40.78 | d | 50.25 | h | 54.34 | f | 67.12 | f | 78.07 | c | 72.09 | h | 62.84 | b | 47.83 | d | 39.37 | g | 34.08 | e | 47.68 | e |
| 2003 | 41.92 | e | 32.89 | f | 42.65 | g | 45.28 | l | 57.02 | h | 67.05 | h | 79.00 | g | 72.10 | e | ----- | z | ----- | z | ----- | z | ----- | z | 57.01 | j |
| 2004 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2005 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2006 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2007 | 22.61 | l | 36.46 | n | 45.60 | j | 50.52 | j | ----- | z | 68.66 | e | 80.04 | g | 75.89 | c | 61.65 | g | 47.74 | n | 42.92 | j | ----- | z | 72.28 | j |
| 2008 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 60.05 | t | ----- | z | ----- | z | 64.28 | a | 52.21 | b | 42.91 | c | 30.22 | d | 47.40 | h |
| 2009 | 33.39 | h | 37.00 | j | 38.33 | p | 46.68 | e | 63.78 | b | 65.50 | e | 76.56 | d | 70.81 | j | 68.11 | k | 49.35 | ----- | z | ----- | z | 60.37 | g | |
| 2010 | ----- | z | ----- | z | ----- | z | ----- | z | 50.42 | 65.35 | 73.93 | j | 70.56 | m | ----- | z | ----- | z | ----- | z | ----- | z | 57.88 | j | ||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 32.91 | 38.43 | 43.48 | 49.05 | 57.46 | 66.00 | 73.15 | 70.45 | 62.82 | 51.44 | 39.80 | 32.03 | 51.04 | |||||||||||||
| S.D. | 4.16 | 2.90 | 3.11 | 3.12 | 3.83 | 2.89 | 2.66 | 3.11 | 2.55 | 2.64 | 3.27 | 4.21 | 1.58 | |||||||||||||
| SKEW | 0.31 | -0.21 | -0.09 | -0.34 | -0.10 | 0.32 | -0.06 | -0.41 | -1.25 | 0.42 | -0.21 | -0.37 | 0.30 | |||||||||||||
| MAX | 41.92 | 44.21 | 49.39 | 54.46 | 64.45 | 72.33 | 78.07 | 75.89 | 67.32 | 57.68 | 46.37 | 39.94 | 53.21 | |||||||||||||
| MIN | 26.52 | 31.54 | 37.33 | 41.63 | 50.27 | 61.47 | 67.79 | 64.02 | 55.48 | 47.61 | 33.00 | 21.28 | 49.40 | |||||||||||||
| YRS | 24 | 24 | 25 | 24 | 27 | 28 | 24 | 26 | 26 | 24 | 24 | 25 | 7 | |||||||||||||