| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1959 | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.14 | 0.30 | 0.00 | 0.00 | i | 0.44 | ||||
| 1960 | 0.63 | 1.43 | 0.82 | 0.19 | 0.44 | 0.01 | 0.56 | 0.13 | 0.17 | 0.02 | 2.59 | 0.53 | 7.52 | |||||||||||||
| 1961 | 0.11 | b | 0.34 | 0.46 | 0.11 | 0.66 | 0.96 | 0.34 | 0.90 | 0.46 | 0.38 | 0.26 | 0.48 | 5.46 | ||||||||||||
| 1962 | 0.34 | 0.88 | 0.29 | 0.00 | 1.34 | 0.31 | 0.05 | 0.17 | 0.04 | 1.46 | 0.44 | 0.21 | 5.53 | |||||||||||||
| 1963 | 0.53 | 0.73 | 0.42 | 0.38 | 1.02 | 2.06 | 0.00 | 0.33 | 0.14 | 0.21 | 0.56 | 0.26 | 6.64 | |||||||||||||
| 1964 | 0.55 | 0.03 | 0.22 | 0.32 | 0.68 | 2.30 | 0.35 | 0.38 | 0.06 | 0.25 | 0.16 | 1.42 | 6.72 | |||||||||||||
| 1965 | 0.98 | 0.02 | 0.10 | 0.13 | 0.68 | 1.58 | 0.14 | 1.48 | 0.00 | 0.04 | 1.02 | 0.49 | 6.66 | |||||||||||||
| 1966 | 0.10 | 1.00 | 0.12 | 0.15 | 0.40 | 0.48 | 0.00 | 0.21 | 0.72 | 0.00 | 0.94 | 0.61 | 4.73 | |||||||||||||
| 1967 | 0.51 | 0.02 | 0.29 | 1.04 | 0.89 | 1.10 | 0.39 | 0.18 | 0.57 | 0.06 | 1.04 | 0.27 | 6.36 | |||||||||||||
| 1968 | 0.34 | 0.40 | 0.08 | 0.05 | 0.64 | 0.63 | 0.10 | 1.20 | 0.00 | 0.32 | 1.36 | 0.18 | 5.30 | |||||||||||||
| 1969 | 1.99 | 0.45 | 0.19 | 0.20 | 0.33 | 2.24 | 0.69 | 0.00 | 0.29 | 1.54 | 0.20 | 1.42 | 9.54 | |||||||||||||
| 1970 | 1.21 | 0.07 | 0.09 | 0.71 | 0.36 | 1.16 | 0.39 | 0.00 | 0.82 | 0.81 | 1.78 | j | 1.23 | 6.85 | ||||||||||||
| 1971 | 0.51 | 0.20 | 0.61 | 0.00 | z | 4.15 | 1.06 | 0.00 | q | 0.02 | 1.56 | 0.56 | 0.81 | 0.81 | 10.29 | |||||||||||
| 1972 | 0.52 | 0.86 | 0.12 | 0.18 | 0.08 | 0.72 | 0.02 | 0.00 | 0.37 | 0.89 | 1.12 | 0.64 | 5.52 | |||||||||||||
| 1973 | 0.56 | 0.62 | 1.14 | 0.53 | 0.20 | 0.00 | 1.16 | 0.32 | 0.32 | 0.28 | 0.84 | c | 0.83 | 6.80 | ||||||||||||
| 1974 | 0.59 | 0.22 | 1.05 | 1.03 | 0.28 | 0.00 | 0.65 | 0.04 | 0.00 | z | 0.00 | z | 0.00 | z | 0.64 | l | 3.86 | |||||||||
| 1975 | 0.35 | 0.50 | 0.52 | 0.61 | 0.15 | 1.24 | 0.39 | 1.65 | 0.39 | 0.79 | f | 0.06 | 0.42 | 6.28 | ||||||||||||
| 1976 | 0.39 | 0.29 | 0.54 | 0.09 | 0.23 | 0.85 | 0.86 | 2.02 | 1.94 | 0.06 | 0.00 | 0.00 | 7.27 | |||||||||||||
| 1977 | 0.44 | 0.12 | 0.25 | 0.26 | 1.87 | 0.69 | 0.52 | 0.17 | 0.19 | 0.19 | 0.74 | 1.91 | 7.35 | |||||||||||||
| 1978 | 1.42 | 0.28 | 2.09 | 2.49 | 0.04 | 0.49 | 0.34 | 0.58 | 1.20 | 0.00 | 1.00 | 0.40 | 10.33 | |||||||||||||
| 1979 | 0.91 | 1.03 | 1.00 | 1.47 | 1.01 | 0.53 | 0.56 | 2.14 | 0.00 | z | 0.40 | d | 0.68 | 1.05 | 10.78 | |||||||||||
| 1980 | 1.89 | 0.43 | 0.18 | b | 0.55 | 1.30 | 0.86 | 0.00 | z | 0.00 | 1.13 | 0.38 | 0.29 | c | 0.13 | k | 7.01 | |||||||||
| 1981 | 0.77 | 0.51 | 1.03 | 0.13 | c | 1.27 | 0.33 | 0.00 | 0.35 | 0.07 | 0.71 | 1.03 | b | 0.66 | 6.86 | |||||||||||
| 1982 | 0.30 | 0.16 | 0.91 | a | 0.08 | b | 0.21 | 2.09 | 0.00 | z | 0.05 | 0.00 | z | 0.00 | z | 0.00 | z | 0.33 | 4.13 | |||||||
| 1983 | 0.40 | c | 0.54 | 1.33 | 1.37 | b | 1.22 | 1.76 | 0.26 | 1.52 | 1.13 | 0.34 | 1.31 | a | 0.00 | z | 11.18 | |||||||||
| 1984 | 1.83 | 0.58 | 0.70 | a | 0.60 | 0.45 | 0.61 | 0.49 | e | 0.36 | 0.96 | 0.98 | 2.33 | 0.88 | 10.77 | |||||||||||
| 1985 | 0.10 | 0.41 | 0.47 | 0.56 | 0.41 | 0.00 | 0.30 | 0.00 | 0.53 | 0.00 | 0.69 | d | 0.06 | f | 3.47 | |||||||||||
| 1986 | 0.16 | 2.25 | 1.72 | a | 1.26 | 0.71 | a | 0.47 | 0.52 | 0.31 | 0.65 | 0.00 | z | 0.07 | 0.44 | b | 8.56 | |||||||||
| 1987 | 0.18 | a | 0.26 | 0.42 | a | 0.81 | k | 2.30 | 0.68 | 0.00 | b | 0.15 | 0.00 | 0.34 | 0.94 | d | 0.00 | z | 5.27 | |||||||
| 1988 | 0.71 | 0.25 | 0.14 | b | 1.74 | 0.16 | b | 0.32 | 0.01 | 0.37 | 0.32 | 0.00 | 0.96 | 0.46 | 5.44 | |||||||||||
| 1989 | 0.37 | 0.39 | 0.25 | 0.21 | b | 1.78 | f | 0.29 | c | 0.00 | 0.38 | 0.51 | 0.42 | 0.24 | 0.20 | 3.26 | ||||||||||
| 1990 | 0.36 | 0.32 | a | 0.29 | 0.73 | c | 0.85 | 0.02 | c | 0.52 | 0.96 | 0.02 | b | 0.10 | a | 0.22 | 0.25 | 4.64 | ||||||||
| 1991 | 0.65 | 0.49 | g | 1.55 | b | 0.71 | a | 1.94 | d | 0.77 | c | 0.16 | 0.59 | d | 0.42 | d | 0.79 | 0.43 | b | 0.62 | 8.63 | |||||
| 1992 | 0.10 | 0.52 | f | 1.09 | 0.13 | 0.04 | 1.01 | 0.32 | 0.06 | 0.03 | 1.47 | 0.38 | d | 1.56 | 6.19 | |||||||||||
| 1993 | 1.69 | 0.49 | b | 0.96 | c | 0.40 | c | 0.87 | a | 2.36 | a | 0.27 | 1.49 | 0.02 | 0.63 | b | 0.56 | b | 0.44 | a | 10.18 | |||||
| 1994 | 0.13 | 0.75 | 0.74 | c | 0.46 | 1.16 | 0.22 | 0.17 | 0.00 | 0.15 | 0.20 | 0.74 | d | 1.58 | 6.30 | |||||||||||
| 1995 | 1.12 | a | 0.22 | 1.10 | 1.58 | n | 1.12 | f | 1.47 | j | 0.80 | f | 0.00 | 0.02 | 0.04 | 0.18 | 1.52 | g | 2.68 | |||||||
| 1996 | 1.67 | k | 1.11 | 0.79 | 0.82 | 1.03 | a | 1.52 | 0.14 | 0.13 | 0.05 | c | 0.71 | g | 0.27 | h | 0.81 | d | 6.40 | |||||||
| 1997 | 0.74 | f | 0.46 | b | 0.15 | e | 0.72 | b | 0.60 | i | 1.04 | h | 0.37 | 0.07 | b | 0.30 | 0.15 | 0.00 | z | 0.00 | z | 2.22 | ||||
| 1998 | 0.00 | z | 0.87 | c | 0.00 | z | 0.95 | a | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.74 | f | 1.82 | |
| 1999 | 0.87 | 0.55 | 0.39 | c | 0.35 | c | 0.12 | 0.83 | 0.00 | 1.20 | b | 0.02 | 0.10 | 0.44 | p | 0.00 | z | 4.43 | ||||||||
| 2000 | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | |
| 2001 | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.14 | 0.96 | 0.55 | 1.65 | ||||
| 2002 | 0.73 | 0.22 | 0.12 | 0.72 | 0.33 | 0.11 | 0.44 | b | 0.02 | 0.00 | 0.14 | t | 0.25 | 0.20 | 3.14 | |||||||||||
| 2003 | 0.23 | 0.35 | 0.14 | 0.34 | 0.73 | 0.26 | 0.39 | a | 1.10 | 0.49 | 0.08 | a | 0.69 | 0.58 | 5.38 | |||||||||||
| 2004 | 0.26 | 0.21 | 0.28 | 0.22 | 1.28 | 0.70 | a | 0.00 | 0.52 | 0.30 | 1.18 | c | 0.80 | 0.31 | 6.06 | |||||||||||
| 2005 | 0.55 | b | 0.11 | 0.28 | 0.38 | b | 3.78 | b | 0.09 | j | 0.02 | 0.11 | a | 0.17 | 0.82 | c | 0.96 | 1.06 | u | 7.18 | ||||||
| 2006 | 0.42 | o | 0.31 | 0.41 | 0.00 | z | 0.17 | y | 0.39 | 0.10 | 0.03 | 0.03 | c | 0.48 | 0.28 | 0.09 | 2.12 | |||||||||
| 2007 | 0.16 | 0.34 | 0.04 | 0.36 | 0.14 | 0.27 | 0.04 | 0.02 | 0.68 | 0.42 | 0.00 | z | 0.21 | c | 2.68 | |||||||||||
| 2008 | 0.45 | 0.23 | 0.08 | 0.07 | i | 1.08 | 0.23 | 0.13 | 0.00 | 0.09 | 0.03 | 0.46 | 0.62 | 3.40 | ||||||||||||
| 2009 | 0.39 | c | 0.05 | 0.13 | 0.30 | 0.00 | z | 3.67 | 0.24 | 0.35 | 0.05 | 0.20 | 0.10 | 0.44 | 5.92 | |||||||||||
| 2010 | 0.60 | 0.26 | 0.52 | 1.04 | 0.91 | 0.25 | 0.12 | 0.12 | 0.31 | 2.56 | 0.22 | 1.15 | 8.06 | |||||||||||||
| 2011 | 0.19 | 0.29 | 0.82 | 0.77 | 1.58 | 0.60 | 0.00 | b | 0.00 | z | 0.01 | 0.55 | 0.29 | 0.04 | 5.14 | |||||||||||
| 2012 | 0.36 | 0.19 | 0.15 | 0.19 | 0.21 | 0.12 | 0.09 | 0.16 | 0.12 | 0.07 | 0.04 | 0.81 | 2.51 | |||||||||||||
| 2013 | 0.74 | 0.13 | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.00 | z | 0.87 | |||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 0.61 | 0.45 | 0.55 | 0.57 | 0.88 | 0.83 | 0.27 | 0.46 | 0.37 | 0.46 | 0.65 | 0.63 | 6.72 | |||||||||||||
| S.D. | 0.48 | 0.40 | 0.47 | 0.50 | 0.87 | 0.78 | 0.26 | 0.58 | 0.44 | 0.52 | 0.55 | 0.46 | 1.93 | |||||||||||||
| SKEW | 1.46 | 2.19 | 1.22 | 1.66 | 2.11 | 1.49 | 1.10 | 1.45 | 1.68 | 1.97 | 1.53 | 1.04 | 0.46 | |||||||||||||
| MAX | 1.99 | 2.25 | 2.09 | 2.49 | 4.15 | 3.67 | 1.16 | 2.14 | 1.94 | 2.56 | 2.59 | 1.91 | 10.77 | |||||||||||||
| MIN | 0.10 | 0.02 | 0.04 | 0.00 | 0.04 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 2.51 | |||||||||||||
| NO YRS | 48 | 50 | 50 | 46 | 45 | 47 | 46 | 49 | 48 | 46 | 45 | 42 | 25 | |||||||||||||