| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1991 | ----- | z | 26.11 | 21.23 | ----- | z | 34.19 | 45.95 | ----- | z | 53.68 | 46.53 | 35.95 | 23.98 | 20.48 | 34.23 | ||||||||||
| 1992 | 20.32 | 22.19 | 26.31 | 36.30 | 39.82 | 47.02 | 51.92 | 51.82 | 46.58 | 36.74 | 16.65 | 15.16 | 34.24 | |||||||||||||
| 1993 | 18.35 | 18.79 | 28.52 | 30.12 | 40.06 | 46.05 | 53.69 | 54.11 | 46.32 | 32.67 | a | 22.78 | 18.48 | a | 34.16 | |||||||||||
| 1994 | 20.12 | a | 18.12 | 28.23 | a | 30.47 | 38.31 | 53.20 | 57.74 | 56.87 | 47.13 | 32.44 | 18.12 | a | 19.19 | 35.00 | ||||||||||
| 1995 | 19.40 | 25.96 | 23.73 | a | 28.53 | 33.15 | 41.52 | 53.58 | 56.02 | 48.27 | 37.47 | a | 31.05 | a | 18.66 | 34.78 | ||||||||||
| 1996 | 19.61 | d | 24.10 | 24.95 | a | 30.52 | 41.69 | 53.97 | 57.76 | 56.02 | 44.40 | 32.45 | 24.98 | a | 18.70 | a | 35.76 | |||||||||
| 1997 | 17.52 | 16.11 | a | 28.75 | a | 28.28 | 41.81 | 50.05 | 53.77 | 55.42 | 46.68 | 35.07 | a | 26.55 | 16.68 | 34.72 | ||||||||||
| 1998 | 19.72 | a | 17.68 | 23.45 | a | 28.07 | 37.38 | a | 46.00 | 56.00 | 55.73 | 48.30 | 34.92 | 25.35 | 19.12 | a | 34.31 | |||||||||
| 1999 | 21.23 | a | 22.88 | 28.27 | 25.36 | a | 37.90 | 47.70 | 53.73 | 52.97 | 46.47 | 39.97 | 31.48 | 18.98 | a | 35.58 | ||||||||||
| 2000 | 20.71 | 23.10 | 24.60 | 36.68 | 44.16 | 54.05 | 57.90 | 56.06 | 49.57 | 36.02 | 18.68 | 22.84 | 37.03 | |||||||||||||
| 2001 | 16.95 | 20.16 | 28.32 | 31.73 | 43.35 | 51.65 | 56.15 | 56.53 | 50.20 | 39.87 | 27.69 | a | 16.38 | a | 36.58 | |||||||||||
| 2002 | 18.15 | 21.41 | 22.70 | a | 36.77 | 42.88 | a | 56.47 | 58.55 | 56.48 | 45.13 | 33.32 | 26.73 | 16.72 | a | 36.28 | ||||||||||
| 2003 | 25.90 | 19.43 | a | ----- | z | 29.57 | a | 42.77 | 52.60 | a | 58.23 | 57.13 | 48.65 | 41.73 | 23.59 | c | 20.02 | b | 38.15 | |||||||
| 2004 | 15.80 | a | 15.41 | 30.73 | a | 32.35 | 43.50 | 49.73 | 54.62 | c | 53.56 | 44.72 | 34.42 | 23.84 | a | 20.10 | b | 34.90 | ||||||||
| 2005 | 21.79 | 23.23 | 24.92 | 30.50 | 40.92 | 49.32 | 58.63 | 52.35 | 45.80 | 33.74 | 28.81 | a | 22.14 | b | 36.01 | |||||||||||
| 2006 | 19.17 | a | 21.14 | 22.19 | b | 35.34 | a | 41.94 | 54.53 | 57.55 | 56.24 | 45.67 | a | 39.35 | n | 31.03 | a | 22.77 | 37.05 | |||||||
| 2007 | 19.59 | b | 26.31 | a | 32.03 | 36.81 | n | ----- | z | ----- | z | 63.61 | h | 60.82 | i | 51.97 | m | 43.22 | v | 36.07 | p | 17.12 | o | 25.98 | ||
| 2008 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 61.79 | g | 60.61 | 50.60 | d | ----- | z | 32.74 | k | 19.98 | 43.73 | |||
| 2009 | 22.73 | e | 21.98 | g | 25.14 | i | 28.42 | r | 50.81 | r | 51.10 | j | 62.08 | m | 58.33 | k | 48.00 | v | 32.58 | m | 31.73 | f | ----- | z | 22.73 | |
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 19.83 | 21.30 | 26.18 | 31.37 | 40.24 | 49.99 | 55.99 | 55.39 | 47.12 | 35.78 | 25.08 | 19.20 | 35.33 | |||||||||||||
| S.D. | 2.34 | 3.39 | 3.18 | 3.49 | 3.28 | 4.07 | 2.24 | 2.13 | 1.86 | 2.91 | 4.53 | 2.18 | 0.94 | |||||||||||||
| SKEW | 0.75 | -0.12 | 0.17 | 0.30 | -0.88 | -0.29 | -0.33 | 0.37 | 0.46 | 0.67 | -0.34 | 0.02 | 0.38 | |||||||||||||
| MAX | 25.90 | 26.31 | 32.03 | 36.77 | 44.16 | 56.47 | 58.63 | 60.61 | 50.60 | 41.73 | 31.48 | 22.84 | 37.03 | |||||||||||||
| MIN | 15.80 | 15.41 | 21.23 | 25.36 | 33.15 | 41.52 | 51.92 | 51.82 | 44.40 | 32.44 | 16.65 | 15.16 | 34.16 | |||||||||||||
| NO YRS | 17 | 17 | 16 | 15 | 16 | 16 | 15 | 17 | 17 | 15 | 16 | 17 | 13 | |||||||||||||