| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1930 | 29.27 | p | 40.29 | 39.26 | 44.23 | 44.81 | 49.00 | 51.48 | 53.68 | 50.03 | 40.65 | 41.73 | 41.32 | 45.13 | ||||||||||||
| 1931 | 45.26 | 37.36 | 40.00 | 41.40 | 46.45 | 50.00 | 53.45 | 56.45 | 58.93 | 55.42 | 45.13 | 37.03 | 47.24 | |||||||||||||
| 1932 | 36.26 | 34.52 | 40.97 | 42.23 | 45.55 | 49.67 | 51.00 | 53.16 | 45.87 | 45.06 | 42.13 | 33.00 | 43.28 | |||||||||||||
| 1933 | 35.35 | 32.71 | 37.03 | 38.33 | 42.81 | 47.57 | 49.32 | 51.65 | 50.20 | ----- | z | ----- | z | 40.03 | 42.50 | |||||||||||
| 1934 | 41.23 | 44.21 | 44.19 | 43.27 | 46.61 | 47.30 | 51.48 | 53.87 | 49.53 | 45.42 | 44.53 | 39.26 | 45.91 | |||||||||||||
| 1935 | 36.13 | 37.32 | 34.81 | 37.73 | 42.77 | 47.97 | 50.19 | 48.29 | 48.17 | 42.13 | 35.33 | 37.48 | 41.53 | |||||||||||||
| 1936 | 38.65 | 32.86 | 36.61 | 43.03 | 46.45 | 51.80 | 52.87 | 54.10 | 43.20 | 42.29 | 36.10 | 39.16 | 43.09 | |||||||||||||
| 1937 | 27.71 | 36.04 | 39.65 | 40.80 | 43.94 | 48.97 | 50.94 | 50.87 | 50.27 | 45.87 | 44.03 | 39.55 | 43.22 | |||||||||||||
| 1938 | 37.94 | 36.39 | 38.32 | 42.10 | 42.94 | 48.63 | 49.97 | 50.68 | 51.13 | 45.47 | a | 39.07 | 37.45 | 43.34 | ||||||||||||
| 1939 | 38.71 | 35.57 | 37.68 | 40.37 | 42.63 | a | 49.20 | 50.35 | 50.97 | 46.93 | 45.03 | 42.47 | 41.45 | 43.45 | ||||||||||||
| 1940 | 38.87 | 41.07 | 40.87 | 42.57 | 44.42 | 48.07 | 51.55 | 52.74 | 52.53 | 48.84 | 37.10 | 39.35 | 44.83 | |||||||||||||
| 1941 | 39.03 | 41.11 | 40.52 | 43.03 | 46.06 | 51.97 | 54.97 | 53.52 | 50.43 | 46.97 | 41.90 | 39.35 | 45.74 | |||||||||||||
| 1942 | 35.26 | 37.00 | 36.94 | 42.97 | 45.45 | 50.27 | 57.90 | 55.19 | 49.13 | 45.94 | 40.77 | 39.61 | 44.70 | |||||||||||||
| 1943 | 31.19 | 38.21 | 37.06 | 42.33 | 44.03 | 49.60 | 52.19 | 52.65 | 48.47 | 46.74 | 40.63 | 36.55 | 43.31 | |||||||||||||
| 1944 | 36.52 | 37.00 | 36.19 | 40.93 | 44.42 | 47.80 | 51.48 | 52.10 | 48.43 | 46.32 | 41.33 | 35.29 | 43.15 | |||||||||||||
| 1945 | 38.23 | 39.39 | 37.42 | 41.07 | 47.03 | 46.47 | 49.74 | 50.39 | 47.80 | 43.48 | 42.10 | 38.16 | 43.44 | |||||||||||||
| 1946 | 39.00 | 38.11 | 38.26 | 40.13 | 46.81 | 48.97 | 52.32 | 51.42 | 49.70 | 42.16 | 37.83 | 38.03 | 43.56 | |||||||||||||
| 1947 | 33.94 | 39.07 | 40.19 | 42.63 | 45.81 | 50.57 | 52.58 | 52.52 | 48.97 | 47.45 | 42.23 | 40.48 | 44.70 | |||||||||||||
| 1948 | 35.06 | 35.59 | 36.97 | 39.40 | 45.84 | 51.77 | 51.48 | 53.77 | 48.40 | 46.23 | 31.43 | 25.32 | 41.77 | |||||||||||||
| 1949 | 25.60 | a | 34.64 | 38.77 | a | 42.10 | 45.45 | 46.17 | 49.45 | 51.90 | 50.13 | 40.35 | 45.00 | 37.42 | 42.25 | |||||||||||
| 1950 | 28.13 | 36.86 | 38.29 | 39.10 | a | 42.13 | 49.50 | 50.48 | 52.03 | 46.73 | 43.55 | 41.73 | 44.00 | 42.71 | ||||||||||||
| 1951 | 36.06 | 37.32 | 35.19 | 38.73 | 44.39 | 49.63 | 52.65 | 50.42 | 47.53 | 45.67 | a | 40.70 | 35.77 | 42.84 | ||||||||||||
| 1952 | 35.81 | 37.10 | 36.06 | 38.30 | 42.68 | 48.77 | 50.68 | 52.70 | a | 47.33 | 46.19 | 34.67 | 38.23 | 42.38 | ||||||||||||
| 1953 | 43.13 | 38.19 | a | 37.84 | 40.37 | 43.81 | 47.40 | 51.29 | 53.32 | 49.27 | 45.71 | 43.87 | 39.81 | 44.50 | ||||||||||||
| 1954 | 34.58 | 37.79 | 33.13 | 39.24 | a | 43.30 | a | 46.70 | 49.42 | 51.42 | 48.76 | a | 41.71 | 44.37 | 38.10 | 42.38 | ||||||||||
| 1955 | 36.35 | 35.75 | 35.13 | a | 36.31 | a | 43.26 | 49.00 | 52.45 | 49.45 | 47.38 | a | 44.93 | b | 38.62 | a | 36.52 | 42.10 | ||||||||
| 1956 | 37.37 | a | 34.07 | a | 36.81 | 40.33 | 45.58 | 48.97 | 52.61 | 52.93 | a | 48.97 | 45.27 | a | 37.37 | 38.03 | 43.19 | |||||||||
| 1957 | 30.94 | 36.64 | 40.00 | 42.20 | 47.10 | 50.50 | 51.10 | 52.23 | a | 50.30 | 44.90 | 38.47 | 39.94 | 43.69 | ||||||||||||
| 1958 | 41.87 | 44.29 | 36.55 | 42.23 | 48.23 | 55.00 | 55.29 | 53.13 | 50.38 | a | 46.29 | 40.77 | 44.55 | 46.55 | ||||||||||||
| 1959 | 40.42 | 38.04 | 40.26 | 43.77 | 44.94 | 51.90 | 51.68 | 52.16 | 50.03 | 46.94 | 37.83 | 35.35 | 44.44 | |||||||||||||
| 1960 | 36.26 | 37.17 | 38.42 | 42.13 | 44.45 | 49.67 | 48.60 | a | 52.74 | 47.20 | 47.29 | 40.27 | 38.00 | 43.52 | ||||||||||||
| 1961 | 40.35 | 42.18 | 39.48 | 41.13 | 44.55 | 48.53 | 53.19 | 52.94 | 48.43 | 43.77 | a | 35.13 | 36.52 | b | 43.85 | |||||||||||
| 1962 | 34.29 | 37.50 | 36.16 | 41.10 | 45.16 | 46.87 | 50.74 | 52.45 | 49.57 | b | 44.77 | 41.41 | a | 37.42 | 43.12 | |||||||||||
| 1963 | 30.55 | 43.00 | 36.45 | 39.73 | 46.97 | 49.80 | 53.00 | b | 53.39 | 52.33 | 46.77 | 42.67 | 39.94 | 44.55 | ||||||||||||
| 1964 | 39.35 | 35.66 | 38.42 | 39.63 | 42.84 | 49.40 | 52.87 | 51.94 | 48.14 | a | 46.03 | 37.20 | 35.87 | 43.11 | ||||||||||||
| 1965 | 36.23 | 39.32 | 37.35 | 41.77 | 44.23 | 47.63 | 51.74 | 54.26 | 49.67 | 48.06 | 45.17 | 36.35 | 44.32 | |||||||||||||
| 1966 | 37.64 | f | 37.57 | 36.97 | 42.93 | 42.71 | 48.50 | 52.94 | 50.61 | 51.23 | 44.77 | 42.73 | 42.71 | 44.88 | ||||||||||||
| 1967 | 40.58 | 38.32 | 37.00 | 36.37 | 44.45 | 51.63 | 52.32 | 53.10 | 50.93 | 48.45 | 42.87 | 38.23 | 44.52 | |||||||||||||
| 1968 | 38.06 | 42.14 | 41.71 | 40.50 | 45.52 | 49.87 | 53.58 | 52.77 | 50.70 | 45.32 | 43.13 | 36.68 | 45.00 | |||||||||||||
| 1969 | 32.65 | 35.93 | 37.84 | 41.73 | 46.32 | 54.00 | 51.94 | 51.26 | 50.83 | 44.61 | 40.20 | 40.13 | 43.95 | |||||||||||||
| 1970 | 38.65 | 40.32 | 38.26 | 39.73 | 43.90 | 48.80 | 51.74 | 51.13 | 47.47 | 44.16 | 42.60 | 36.97 | 43.64 | |||||||||||||
| 1971 | 37.52 | 37.50 | 36.03 | 39.60 | 44.58 | 48.20 | 50.39 | 53.87 | 47.67 | 42.55 | 41.63 | 36.35 | 42.99 | |||||||||||||
| 1972 | 34.68 | 35.76 | 40.03 | 38.13 | 45.55 | 48.90 | 51.61 | 51.06 | 46.17 | 41.81 | 41.83 | 34.35 | 42.49 | |||||||||||||
| 1973 | 36.39 | 38.11 | 38.90 | 41.47 | 45.00 | 49.70 | 50.16 | 49.81 | 48.87 | 44.13 | 38.63 | 40.26 | 43.45 | |||||||||||||
| 1974 | 34.77 | 37.89 | 39.42 | 41.83 | 44.35 | 46.77 | 48.39 | 51.23 | 48.27 | 40.97 | 40.59 | a | 39.55 | 42.84 | ||||||||||||
| 1975 | 37.37 | d | 35.96 | 36.35 | 36.70 | c | 43.77 | 48.33 | 52.29 | 52.48 | b | 49.21 | a | 46.89 | c | 39.85 | c | 39.45 | 43.22 | |||||||
| 1976 | 37.93 | a | 36.29 | a | 36.10 | b | 40.00 | b | 43.68 | f | 47.09 | g | 50.21 | g | 52.11 | d | 52.14 | b | 44.77 | 39.79 | b | 38.43 | c | 41.95 | ||
| 1977 | 34.00 | b | 40.50 | 37.97 | 41.38 | a | 44.07 | b | 49.21 | a | 50.14 | c | 53.45 | b | 49.20 | 43.27 | a | 39.75 | b | 40.10 | a | 43.59 | ||||
| 1978 | 40.42 | 41.48 | c | 38.93 | d | 40.79 | f | 44.03 | b | 50.42 | d | 51.96 | g | 53.08 | f | 50.57 | i | 43.89 | d | 34.15 | c | 32.60 | a | 40.74 | ||
| 1979 | 32.38 | b | 37.81 | b | 38.85 | d | 41.83 | 45.42 | 47.00 | 52.55 | b | 52.80 | a | 51.38 | a | 48.04 | c | 36.88 | d | 42.45 | b | 43.95 | ||||
| 1980 | 32.33 | a | 40.50 | a | 40.44 | f | 40.80 | 44.94 | 48.39 | b | 52.23 | ----- | z | 48.32 | e | 43.84 | 42.72 | a | 40.13 | 43.42 | ||||||
| 1981 | 40.07 | b | 37.65 | e | 38.93 | a | 40.89 | b | 44.96 | c | 49.59 | a | 50.62 | e | 51.93 | b | 46.62 | i | 40.45 | b | 38.57 | b | 35.33 | a | 42.64 | |
| 1982 | 33.61 | 36.71 | 36.77 | 36.87 | 42.39 | 49.40 | 51.03 | 51.06 | ----- | z | 46.13 | 37.27 | 36.61 | 41.62 | ||||||||||||
| 1983 | 40.35 | 41.36 | 39.65 | 37.83 | 45.77 | 48.17 | 53.35 | 52.26 | 46.24 | a | 40.26 | 43.13 | 30.81 | 43.27 | ||||||||||||
| 1984 | 37.68 | 38.97 | 41.58 | 40.17 | 43.97 | 48.10 | 48.58 | 48.90 | 47.33 | 43.90 | 40.10 | 34.39 | 42.81 | |||||||||||||
| 1985 | 30.94 | 32.18 | 33.19 | 40.37 | 43.32 | 46.70 | 50.23 | 49.29 | 46.47 | 44.00 | 33.60 | 31.10 | 40.11 | |||||||||||||
| 1986 | 40.29 | 37.75 | 41.94 | 40.00 | 44.84 | 48.60 | 51.68 | 51.03 | 47.87 | 45.87 | 42.07 | 38.03 | 44.16 | |||||||||||||
| 1987 | 36.90 | 39.50 | 39.03 | b | 41.60 | 46.65 | 46.67 | 51.71 | 50.87 | 48.10 | 42.74 | 43.70 | 35.39 | 43.57 | ||||||||||||
| 1988 | 37.26 | 39.03 | 39.58 | 42.60 | 45.45 | 47.50 | 50.97 | 50.94 | 47.27 | 49.19 | 44.23 | 38.90 | 44.41 | |||||||||||||
| 1989 | 39.00 | 31.57 | 39.58 | 43.27 | 45.26 | 51.67 | 52.48 | 53.84 | 48.47 | 44.90 | 42.90 | 38.35 | 44.27 | |||||||||||||
| 1990 | 39.94 | 36.64 | 40.13 | 44.60 | 46.35 | 50.93 | 53.39 | 54.58 | 51.73 | 44.94 | 43.73 | 31.61 | 44.88 | |||||||||||||
| 1991 | 35.94 | 41.68 | 36.81 | 41.60 | 46.10 | 49.20 | 52.23 | 54.35 | 49.63 | 43.19 | 43.90 | 41.16 | 44.65 | |||||||||||||
| 1992 | 41.16 | 41.83 | 41.61 | 45.07 | 45.71 | 51.83 | 53.13 | 53.06 | 49.13 | 46.55 | 42.97 | 36.39 | 45.70 | |||||||||||||
| 1993 | 34.16 | 34.54 | 41.52 | 44.37 | 48.90 | 51.00 | 54.35 | 53.39 | 48.07 | 46.97 | 35.57 | 38.13 | 44.25 | |||||||||||||
| 1994 | 40.45 | 37.29 | 40.71 | 44.67 | 45.97 | 49.53 | 52.68 | 54.16 | 51.53 | 44.00 | 37.93 | 39.00 | 44.83 | |||||||||||||
| 1995 | 43.06 | 40.54 | 37.65 | 41.17 | 47.26 | 50.03 | 54.68 | 50.87 | 54.43 | 46.03 | 44.73 | 41.16 | 45.97 | |||||||||||||
| 1996 | 38.94 | 37.21 | 40.65 | 45.00 | 45.42 | 48.87 | 51.65 | 51.03 | 47.97 | 44.48 | 42.50 | 38.06 | 44.31 | |||||||||||||
| 1997 | 39.65 | 38.43 | 40.45 | 41.70 | 48.26 | 51.53 | 54.10 | 55.68 | 53.80 | 47.61 | ----- | z | 38.48 | 46.34 | ||||||||||||
| 1998 | 41.16 | 41.04 | 41.19 | 39.63 | 47.06 | 52.33 | 54.87 | 53.10 | a | 48.97 | 45.58 | 43.70 | 37.19 | 45.49 | ||||||||||||
| 1999 | 39.03 | a | 39.64 | 37.70 | a | 38.30 | 43.13 | 49.13 | 51.21 | b | 53.69 | b | 46.18 | b | 43.71 | 44.31 | a | 40.43 | a | 43.87 | ||||||
| 2000 | 37.03 | a | 39.17 | 37.97 | a | 41.74 | c | 46.32 | 49.64 | b | 52.15 | e | 52.62 | b | 50.10 | a | 46.10 | a | 37.40 | 38.61 | 44.07 | |||||
| 2001 | 38.29 | 34.68 | 39.90 | a | 40.17 | a | 43.65 | 47.53 | 51.89 | c | 53.69 | b | 49.18 | b | 45.19 | 42.32 | k | 33.00 | z | 44.42 | ||||||
| 2002 | 35.31 | o | 37.57 | 37.42 | 40.50 | 42.94 | 49.90 | a | 52.32 | 50.90 | 47.43 | 43.00 | 41.47 | 40.26 | 43.97 | |||||||||||
| 2003 | 42.94 | 35.89 | 41.71 | g | 41.73 | 43.16 | 49.04 | f | 52.45 | 52.04 | d | 49.03 | 48.97 | 38.77 | 39.26 | 44.42 | ||||||||||
| 2004 | 39.55 | 39.17 | 40.65 | 40.50 | 48.06 | 50.90 | 54.29 | 56.23 | 50.20 | 45.79 | g | 39.19 | d | 40.39 | m | 45.87 | ||||||||||
| 2005 | ----- | z | 35.39 | 39.52 | 43.30 | 49.35 | 50.20 | 52.33 | g | 51.47 | n | 44.11 | k | 46.84 | f | 38.70 | g | 38.13 | 42.65 | |||||||
| 2006 | 41.39 | 35.79 | 37.00 | 40.27 | ----- | z | 50.67 | 52.06 | 51.10 | k | 46.35 | g | 41.55 | 42.81 | i | 38.52 | h | 42.67 | ||||||||
| 2007 | 33.25 | c | 38.43 | 41.08 | g | 39.60 | e | 43.55 | 47.80 | e | 60.39 | m | 52.50 | e | 47.71 | f | 42.88 | g | 39.25 | f | 38.11 | l | 42.52 | |||
| 2008 | 38.76 | j | 39.45 | g | 37.23 | e | 36.93 | 47.15 | d | 48.82 | h | 52.13 | p | 54.19 | e | 49.61 | g | 44.16 | 44.50 | 35.52 | 42.81 | |||||
| 2009 | 37.83 | g | 34.71 | g | 37.84 | 40.44 | e | 44.29 | 51.17 | 50.28 | m | 54.52 | 51.03 | 46.43 | h | 45.03 | 32.21 | g | 46.33 | |||||||
| 2010 | 44.09 | i | 41.25 | 39.76 | f | 41.90 | 43.65 | e | 48.22 | g | 50.83 | h | 51.33 | m | ----- | z | 43.71 | g | 40.60 | 40.65 | 41.61 | |||||
| 2011 | 38.94 | 34.85 | b | 38.56 | f | 37.92 | e | 43.65 | h | 50.18 | m | 49.84 | l | 54.42 | l | 48.06 | l | 46.00 | l | 35.94 | m | 34.04 | f | 37.23 | ||
| 2012 | 37.83 | g | 37.12 | e | 37.48 | 42.36 | e | 44.41 | d | 49.48 | c | ----- | z | 54.00 | z | 47.05 | j | 44.08 | e | 43.80 | 39.62 | e | 42.29 | |||
| 2013 | 35.61 | 40.04 | e | 39.96 | g | 43.00 | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 37.83 | ||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 37.05 | 37.91 | 38.40 | 40.94 | 45.02 | 49.34 | 51.90 | 52.42 | 49.22 | 45.01 | 40.71 | 37.93 | 43.81 | |||||||||||||
| S.D. | 3.71 | 2.61 | 2.05 | 2.03 | 1.61 | 1.72 | 1.66 | 1.61 | 2.23 | 2.42 | 3.15 | 3.02 | 1.23 | |||||||||||||
| SKEW | -0.65 | 0.12 | -0.01 | -0.24 | 0.44 | 0.60 | 0.49 | -0.04 | 1.10 | 0.78 | -0.70 | -1.15 | 0.13 | |||||||||||||
| MAX | 45.26 | 44.29 | 44.19 | 45.07 | 49.35 | 55.00 | 57.90 | 56.45 | 58.93 | 55.42 | 45.17 | 44.55 | 47.24 | |||||||||||||
| MIN | 25.60 | 31.57 | 33.13 | 36.31 | 42.13 | 46.17 | 48.39 | 48.29 | 43.20 | 40.26 | 31.43 | 25.32 | 40.11 | |||||||||||||
| NO YRS | 76 | 82 | 78 | 82 | 80 | 78 | 74 | 76 | 73 | 76 | 76 | 77 | 62 | |||||||||||||