| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1918 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 0.23 | 0.16 | 1.02 | 0.18 | 0.35 | ----- | z | |||||
| 1919 | 0.06 | 0.38 | 0.30 | 0.40 | 0.50 | 0.10 | 0.61 | 0.25 | 0.42 | 0.43 | ----- | z | 0.73 | ----- | z | |||||||||||
| 1920 | 0.24 | 0.60 | 0.42 | 0.20 | 0.22 | 0.22 | 0.48 | 0.42 | 0.22 | 0.51 | 0.17 | 0.08 | 0.60 | |||||||||||||
| 1921 | 0.40 | 0.39 | 0.04 | 0.01 | 0.08 | 0.25 | 0.74 | 1.92 | 0.02 | ----- | z | ----- | z | ----- | z | ----- | z | |||||||||
| 1922 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 0.02 | 0.20 | 0.40 | 0.33 | ----- | z | ||||
| 1923 | 0.23 | 0.25 | 0.30 | 0.33 | 0.48 | 0.00 | 0.36 | 0.42 | 1.25 | 0.70 | 0.60 | x | 0.55 | w | ----- | z | ||||||||||
| 1924 | 0.15 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | |
| 1925 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1926 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1927 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1928 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1929 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1930 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1931 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1932 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1933 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1934 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1935 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1936 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1937 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1938 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1939 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1940 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1941 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1942 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1943 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1944 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1945 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1946 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1947 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1948 | ----- | z | ----- | z | ----- | z | 0.02 | w | 0.26 | g | 0.53 | 1.19 | 0.68 | 0.89 | 0.63 | a | 0.10 | 0.55 | ----- | z | ||||||
| 1949 | 0.32 | 0.07 | 0.18 | 0.17 | 0.45 | 0.45 | 1.18 | 0.48 | 0.41 | 0.22 | 0.06 | 0.16 | 1.18 | |||||||||||||
| 1950 | 0.11 | 0.33 | 0.22 | 0.01 | 0.02 | 0.06 | 1.47 | 0.09 | 0.42 | 0.00 | 0.50 | 0.00 | 1.47 | |||||||||||||
| 1951 | 0.21 | 0.01 | f | 0.04 | a | 0.31 | 0.22 | 0.00 | 0.46 | 0.55 | 0.75 | 0.56 | 0.32 | 0.30 | 0.75 | g | ||||||||||
| 1952 | 0.62 | 0.30 | 0.38 | 0.83 | 0.05 | 0.94 | 0.20 | 0.82 | 0.56 | 0.00 | 0.58 | 0.15 | 0.94 | |||||||||||||
| 1953 | 0.09 | 0.09 | 0.22 | 0.33 | 0.11 | 0.10 | 0.41 | 0.41 | 0.03 | 0.25 | 0.29 | 0.28 | 0.41 | |||||||||||||
| 1954 | 0.21 | 0.29 | 1.09 | 0.17 | 0.60 | 0.14 | 1.90 | 0.42 | 0.35 | 0.22 | 0.00 | 0.32 | 1.90 | |||||||||||||
| 1955 | 0.43 | 0.45 | 0.00 | 0.27 | 0.38 | 0.64 | 0.85 | 0.25 | 0.05 | 0.00 | 0.25 | 0.75 | 0.85 | |||||||||||||
| 1956 | 0.45 | 0.30 | ----- | z | ----- | z | 0.00 | 0.00 | 0.46 | 0.75 | b | 0.00 | 0.29 | 0.02 | 0.06 | ----- | z | |||||||||
| 1957 | 0.46 | 0.48 | 0.25 | 1.25 | 0.36 | 0.13 | 0.80 | 0.47 | 0.00 | 0.80 | a | 0.27 | 0.30 | 1.25 | a | |||||||||||
| 1958 | ----- | z | ----- | z | ----- | z | 0.09 | b | 0.21 | 0.00 | b | 1.28 | 1.23 | 0.75 | 0.77 | 0.21 | 0.66 | ----- | z | |||||||
| 1959 | 0.03 | 0.23 | ----- | z | ----- | z | ----- | z | ----- | z | 0.36 | 0.90 | 0.10 | 0.65 | 0.33 | 0.40 | ----- | z | ||||||||
| 1960 | 0.39 | 0.40 | 0.15 | 0.20 | 0.29 | 0.40 | 0.00 | 0.32 | 0.02 | 0.56 | 0.01 | 0.18 | 0.56 | |||||||||||||
| 1961 | 0.06 | 0.20 | 0.08 | 0.20 | 0.09 | 0.01 | 0.85 | a | 0.55 | 0.60 | 0.80 | 0.46 | 0.35 | 0.85 | a | |||||||||||
| 1962 | 0.59 | 0.68 | b | 0.33 | 0.11 | 0.09 | 0.26 | 0.23 | 0.16 | 0.50 | 1.05 | 0.76 | 0.08 | 1.05 | b | |||||||||||
| 1963 | 0.64 | 0.47 | 0.33 | 0.00 | 0.01 | 0.00 | 0.54 | 0.83 | a | 0.75 | 0.44 | 0.29 | 0.21 | 0.83 | a | |||||||||||
| 1964 | 0.20 | 0.31 | 0.44 | 0.14 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 0.03 | ----- | z | |||||
| 1965 | ----- | z | 0.03 | ----- | z | 0.00 | 0.20 | 0.70 | 1.10 | 0.22 | 0.27 | 0.71 | 0.55 | 1.30 | ----- | z | ||||||||||
| 1966 | 0.17 | 0.12 | 0.30 | 0.30 | 0.00 | 0.17 | 0.50 | 0.83 | 0.53 | 0.60 | 0.22 | 0.96 | 0.96 | |||||||||||||
| 1967 | 0.00 | 0.00 | 0.20 | 0.00 | 0.20 | 0.86 | 0.81 | 1.31 | 0.58 | 0.00 | 0.05 | 0.65 | a | 1.31 | a | |||||||||||
| 1968 | 0.09 | 0.00 | 0.00 | e | 0.10 | b | 0.00 | ----- | z | 0.00 | ----- | z | 0.11 | ----- | z | 0.40 | 0.60 | ----- | z | |||||||
| 1969 | 0.11 | 0.04 | 0.72 | a | 0.00 | 0.07 | 0.03 | 0.55 | 0.39 | 0.37 | 0.25 | v | 0.25 | 0.10 | 0.72 | w | ||||||||||
| 1970 | 0.05 | 0.01 | 0.34 | 0.17 | 0.14 | 0.31 | 0.20 | 0.53 | 1.13 | 0.39 | 0.10 | 0.11 | 1.13 | |||||||||||||
| 1971 | 0.15 | 0.13 | a | 0.11 | 0.03 | 0.08 | 0.00 | 0.37 | 0.61 | 1.28 | 0.45 | 0.15 | 0.25 | 1.28 | a | |||||||||||
| 1972 | 0.03 | 0.00 | 0.01 | 0.04 | 0.18 | 0.27 | 0.58 | 0.76 | 0.24 | 1.34 | 0.36 | 0.29 | 1.34 | |||||||||||||
| 1973 | 0.21 | 0.45 | 0.22 | 0.30 | 0.83 | 0.46 | 0.48 | 0.41 | 0.25 | 0.37 | 0.10 | 0.04 | 0.83 | |||||||||||||
| 1974 | 0.52 | 0.15 | 0.06 | 0.32 | 0.00 | 0.00 | 0.79 | 1.34 | 0.39 | 1.20 | 0.33 | 0.03 | 1.34 | |||||||||||||
| 1975 | 0.18 | 0.25 | 0.30 | 0.08 | 0.10 | 0.05 | 0.55 | 0.20 | 0.70 | 0.00 | 0.03 | 0.03 | 0.70 | |||||||||||||
| 1976 | 0.00 | 0.00 | 0.00 | 0.00 | 0.49 | 0.25 | 0.36 | 0.41 | 0.51 | 0.31 | 0.20 | 0.00 | 0.51 | |||||||||||||
| 1977 | 0.08 | a | 0.08 | 0.05 | 0.05 | ----- | z | 0.06 | 0.96 | 0.99 | 0.24 | 0.43 | 0.00 | 0.00 | ----- | z | ||||||||||
| 1978 | 0.41 | 0.41 | 0.27 | 0.00 | 0.28 | 0.14 | 0.32 | 0.36 | 0.51 | 1.20 | 0.95 | 0.21 | 1.20 | |||||||||||||
| 1979 | 0.38 | 0.10 | 0.24 | 0.00 | 0.35 | 0.50 | 0.01 | 0.67 | 0.00 | 1.20 | 1.25 | a | 0.70 | a | 1.25 | b | ||||||||||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 0.24 | 0.24 | 0.24 | 0.19 | 0.22 | 0.24 | 0.63 | 0.61 | 0.42 | 0.54 | 0.30 | 0.32 | 1.03 | |||||||||||||
| S.D. | 0.19 | 0.19 | 0.22 | 0.26 | 0.20 | 0.26 | 0.43 | 0.39 | 0.35 | 0.38 | 0.28 | 0.30 | 0.35 | |||||||||||||
| SKEW | 0.61 | 0.39 | 1.89 | 2.59 | 1.06 | 1.13 | 0.92 | 1.39 | 0.82 | 0.42 | 1.63 | 1.27 | 0.24 | |||||||||||||
| MAX | 0.64 | 0.68 | 1.09 | 1.25 | 0.83 | 0.94 | 1.90 | 1.92 | 1.28 | 1.34 | 1.25 | 1.30 | 1.90 | |||||||||||||
| MIN | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.09 | 0.00 | 0.00 | 0.00 | 0.00 | 0.41 | |||||||||||||
| YRS | 34 | 33 | 31 | 33 | 32 | 33 | 35 | 35 | 37 | 34 | 34 | 36 | 23 | |||||||||||||