YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
1935 | ----- | z | ----- | z | 30.84 | 39.20 | 41.77 | 52.30 | 57.19 | 58.23 | 52.13 | 47.06 | 36.07 | o | 31.06 | 45.53 | c | |||||||||
1936 | 27.32 | 30.52 | 33.39 | 40.57 | 45.52 | 53.83 | a | 58.77 | 58.55 | 50.17 | 42.74 | 34.47 | 29.45 | 42.11 | ||||||||||||
1937 | 13.87 | 26.63 | a | 34.20 | a | 40.90 | 47.94 | 50.03 | 58.06 | 57.16 | 52.07 | 41.06 | 33.13 | 31.48 | 40.55 | |||||||||||
1938 | 28.71 | 27.93 | 30.48 | 35.20 | 42.00 | 50.47 | 55.13 | 56.84 | 52.24 | e | 40.58 | 29.00 | 28.90 | 39.79 | ||||||||||||
1939 | 25.26 | 19.32 | 31.94 | 38.83 | 45.42 | 54.73 | 61.26 | 59.19 | 54.13 | 39.90 | 35.55 | a | 32.68 | 41.52 | ||||||||||||
1940 | 30.39 | h | 29.83 | 34.29 | 38.97 | 46.16 | 54.53 | 58.93 | b | 56.97 | 52.10 | 42.56 | d | 31.75 | b | ----- | z | 44.61 | b | |||||||
1941 | ----- | z | ----- | z | ----- | z | 31.91 | h | ----- | z | 49.00 | a | 57.03 | a | 55.61 | 48.27 | 37.87 | 36.40 | o | 27.35 | 45.86 | f | ||||
1942 | 25.74 | 23.46 | 27.26 | 34.87 | 39.87 | a | 47.80 | 57.23 | 54.87 | 49.13 | ----- | z | ----- | z | ----- | z | 40.03 | c | ||||||||
1943 | ----- | z | ----- | z | 34.71 | 40.40 | 45.55 | 50.40 | 57.52 | 57.97 | 50.82 | b | ----- | z | 34.26 | c | 27.97 | a | 44.40 | c | ||||||
1944 | 26.37 | a | 27.72 | 28.68 | 33.76 | a | 42.45 | 46.31 | a | 55.48 | 56.35 | 51.87 | 44.04 | e | 31.55 | a | 28.55 | 39.43 | ||||||||
1945 | 27.45 | 28.82 | 27.06 | 32.66 | a | 41.35 | e | 47.92 | d | 59.68 | 58.94 | 52.27 | 48.50 | q | 33.41 | a | 28.39 | 39.81 | a | |||||||
1946 | 28.29 | c | ----- | z | ----- | z | 41.30 | 44.29 | 52.70 | 59.34 | b | 59.26 | 55.87 | ----- | z | 35.60 | y | 31.97 | a | 46.63 | d | |||||
1947 | 23.55 | 32.93 | a | 33.40 | a | 38.21 | a | 46.63 | a | 51.67 | 58.84 | 58.17 | a | 56.43 | 43.00 | c | 29.64 | h | 24.58 | e | 42.49 | a | ||||
1948 | 30.71 | q | 25.72 | d | 26.62 | g | 37.36 | p | 44.24 | n | 51.29 | f | 57.45 | i | 57.61 | h | 52.30 | g | 43.55 | k | 29.50 | f | 25.74 | l | 25.72 | k |
1949 | 17.32 | f | 18.88 | d | 30.75 | s | 39.95 | i | 43.83 | h | 51.12 | e | 58.96 | f | 55.17 | g | 54.38 | n | 46.17 | s | 37.10 | i | 22.85 | k | 35.00 | j |
1950 | 21.58 | l | 29.53 | k | 30.78 | h | 38.36 | h | 40.79 | q | 48.30 | c | 58.23 | 55.13 | h | 49.17 | g | 43.48 | j | 36.57 | b | 33.32 | i | 47.70 | i | |
1951 | 26.19 | e | 29.67 | a | 29.56 | f | 37.28 | e | 44.00 | d | 47.95 | i | 60.25 | g | 56.68 | i | 50.06 | l | 41.35 | k | 32.19 | i | 26.11 | d | 32.65 | g |
1952 | 26.71 | c | 26.43 | f | 27.29 | c | 38.85 | d | 44.91 | i | 48.11 | c | 56.44 | d | 60.00 | h | 51.86 | i | 44.52 | j | 30.33 | i | 23.78 | m | 39.48 | g |
1953 | 29.50 | o | ----- | z | 32.86 | q | 37.57 | b | 40.00 | a | 51.62 | a | 60.73 | a | 57.57 | c | 52.67 | f | 41.58 | g | 35.68 | h | 26.91 | i | 49.50 | g |
1954 | 28.44 | f | 31.69 | b | 30.93 | d | 41.03 | 46.18 | c | 53.14 | a | 60.81 | 57.50 | e | 53.00 | c | 43.92 | e | 38.04 | e | 31.45 | i | 45.62 | b | ||
1955 | 22.48 | d | 22.35 | b | 30.96 | c | 35.54 | b | 43.66 | b | 49.93 | 56.10 | b | 58.46 | c | 51.74 | c | 45.57 | a | 34.37 | c | 31.55 | b | 40.23 | ||
1956 | 31.79 | b | 24.54 | a | 31.45 | b | 37.17 | a | 47.00 | a | 54.66 | a | 58.13 | a | 54.96 | d | 54.72 | a | 41.67 | d | 29.67 | c | 28.61 | c | 41.20 | |
1957 | 30.47 | a | 35.39 | 34.42 | 36.21 | a | 41.13 | 53.07 | a | 58.74 | 58.09 | i | 50.87 | 43.63 | d | 30.21 | f | 32.71 | 41.66 | b | ||||||
1958 | 27.83 | a | 32.20 | c | 31.20 | a | 36.80 | 48.30 | d | 53.97 | a | 59.21 | b | 60.00 | a | 53.48 | a | 44.52 | b | 34.00 | a | 32.31 | b | 42.82 | ||
1959 | 29.00 | a | 26.56 | c | 32.45 | 40.96 | b | 43.77 | 55.34 | a | 60.20 | a | 58.74 | 52.38 | a | 43.13 | 35.03 | a | 33.96 | g | 43.42 | a | ||||
1960 | 22.40 | a | 25.04 | a | 34.48 | 38.83 | 44.77 | a | 54.90 | a | 59.48 | b | 58.81 | 54.40 | 42.53 | a | 36.24 | e | 28.84 | 41.73 | ||||||
1961 | 30.48 | 30.18 | 32.40 | a | 38.70 | 43.00 | 55.23 | 59.59 | b | 59.07 | a | 50.27 | 40.94 | 31.76 | a | 26.50 | a | 41.51 | ||||||||
1962 | 26.63 | a | 30.68 | 28.08 | e | 41.68 | b | 42.70 | a | 50.62 | a | 58.26 | 58.39 | 53.64 | b | 43.03 | a | 36.54 | f | 32.44 | f | 43.37 | b | |||
1963 | 22.32 | f | 32.62 | b | 31.62 | b | 36.70 | 46.07 | a | 49.96 | c | 61.07 | a | 58.48 | 54.03 | 46.06 | 36.61 | b | 27.48 | h | 45.32 | b | ||||
1964 | 24.07 | b | 24.15 | c | 26.81 | 36.37 | 43.33 | a | 51.85 | c | 61.06 | 58.19 | 52.43 | 45.93 | a | 31.28 | a | 28.65 | h | 41.41 | a | |||||
1965 | 30.81 | e | 27.67 | a | 30.35 | 36.17 | a | 42.50 | a | 47.40 | 59.40 | a | 57.23 | 49.57 | 44.10 | 38.03 | a | 29.84 | f | 42.11 | a | |||||
1966 | 22.36 | f | 22.39 | e | 32.73 | a | 39.57 | 47.55 | 53.03 | 60.16 | 58.74 | 54.17 | 43.06 | 36.72 | a | 31.14 | c | 43.57 | a | |||||||
1967 | 27.31 | e | 30.07 | 34.66 | b | 34.87 | 44.42 | 50.23 | 60.26 | 58.00 | c | 53.60 | 43.23 | a | 37.07 | c | 22.85 | k | 43.07 | a | ||||||
1968 | 26.82 | i | 33.50 | m | 34.34 | b | 36.14 | a | 45.16 | 52.67 | 58.81 | 55.50 | a | 51.03 | 44.23 | 34.87 | 23.32 | c | 43.61 | b | ||||||
1969 | 33.31 | e | 28.83 | j | 26.84 | f | 38.28 | a | 45.77 | a | 51.40 | 60.23 | 60.87 | 53.67 | 40.85 | d | 35.27 | 32.20 | a | 45.18 | b | |||||
1970 | 29.36 | c | 31.79 | i | 31.29 | 33.17 | 45.29 | 53.60 | 60.42 | 60.35 | 50.20 | 39.00 | 34.76 | e | 27.84 | f | 43.74 | b | ||||||||
1971 | 26.28 | f | 28.05 | g | 32.94 | 36.90 | 41.61 | 50.97 | 60.26 | 58.58 | 52.43 | 39.26 | 33.76 | a | 24.25 | k | 45.19 | c | ||||||||
1972 | 26.67 | j | 29.41 | g | 37.77 | 38.59 | a | 44.52 | 53.53 | 59.94 | 57.77 | 51.90 | 43.89 | c | 32.41 | a | 26.25 | g | 46.70 | c | ||||||
1973 | 25.54 | c | 31.05 | g | 28.84 | 34.77 | 46.39 | 53.60 | 58.42 | 58.00 | 50.77 | 42.87 | 33.97 | 30.38 | j | 43.32 | b | |||||||||
1974 | 27.30 | a | 27.88 | d | 35.23 | a | 36.43 | 46.30 | a | 56.63 | 58.87 | 56.26 | 52.70 | 45.07 | a | 34.11 | c | 26.29 | j | 43.34 | a | |||||
1975 | 23.03 | a | 27.56 | c | 29.74 | d | 32.93 | 42.35 | 50.43 | 58.39 | 55.94 | 52.10 | 40.67 | a | 32.13 | 29.28 | f | 40.48 | a | |||||||
1976 | 27.44 | d | 32.08 | d | 30.30 | a | 35.57 | b | 44.97 | 49.43 | 57.32 | 54.52 | 51.17 | 40.61 | 33.81 | d | 27.38 | j | 41.57 | a | ||||||
1977 | 24.70 | h | 28.92 | b | 28.76 | f | 36.63 | 40.90 | 51.37 | 58.00 | 58.42 | 53.07 | 44.69 | b | 35.40 | 32.04 | h | 45.27 | c | |||||||
1978 | 30.53 | a | 28.30 | h | 35.56 | d | 37.03 | 42.94 | 52.80 | 57.71 | 55.13 | 44.90 | a | 30.59 | b | 29.66 | a | 24.55 | b | 40.13 | a | |||||
1979 | 21.14 | c | 25.04 | b | 30.58 | g | 34.42 | d | 43.44 | f | 48.75 | f | 55.62 | b | 54.34 | b | 48.30 | c | 42.50 | a | 25.28 | e | 27.00 | e | 37.07 | c |
1980 | 28.92 | g | 29.43 | f | 28.91 | i | 33.95 | i | 39.22 | d | 45.40 | j | 55.84 | l | 52.80 | f | 51.11 | c | 41.39 | c | 34.50 | b | 34.31 | b | 40.11 | g |
1981 | 32.00 | 29.83 | d | 31.67 | a | 38.88 | e | 44.61 | c | 55.69 | a | 60.40 | a | 58.03 | 52.93 | 42.04 | d | 36.20 | 31.71 | 42.83 | ||||||
1982 | 26.42 | 30.07 | 32.93 | a | 35.18 | h | 43.70 | k | 46.83 | 55.70 | a | 58.93 | a | 51.70 | c | 37.10 | 34.59 | c | 26.16 | 40.04 | b | |||||
1983 | 28.94 | 30.29 | 31.87 | 32.03 | 41.13 | 49.13 | 57.03 | 57.35 | 54.30 | 42.58 | 33.03 | 30.72 | b | 40.70 | ||||||||||||
1984 | 28.42 | 26.52 | 30.97 | 35.50 | 46.84 | 50.90 | 59.29 | 57.06 | 51.80 | 36.77 | 30.52 | c | 29.06 | 40.30 | ||||||||||||
1985 | 26.74 | 24.93 | 31.74 | 39.03 | 43.35 | 52.37 | 58.77 | 55.97 | 46.77 | 42.38 | b | 30.60 | 28.55 | 40.10 | ||||||||||||
1986 | 31.28 | b | 33.48 | a | 36.00 | 38.62 | a | 45.71 | 53.82 | h | 57.81 | e | 59.77 | e | 48.11 | b | 39.78 | d | 34.04 | d | 29.81 | d | 41.31 | a | ||
1987 | 25.23 | a | 28.71 | 30.19 | d | 39.83 | a | ----- | z | 53.34 | a | 56.58 | 57.63 | a | 51.20 | 47.20 | a | 33.83 | a | 26.57 | c | 40.94 | a | |||
1988 | 28.07 | a | 31.62 | 31.45 | b | 38.24 | a | 44.97 | a | 54.10 | a | 59.26 | 58.77 | a | 50.71 | b | 47.58 | 33.90 | 27.50 | a | 42.18 | |||||
1989 | 25.42 | 29.84 | c | 36.00 | a | 44.27 | 47.97 | 53.60 | 60.48 | 56.83 | a | 52.93 | 43.61 | 35.90 | 29.45 | b | 43.03 | |||||||||
1990 | 26.97 | 27.42 | b | 34.53 | a | 42.27 | 44.61 | 55.73 | 59.13 | 56.26 | 55.13 | 42.94 | 34.96 | b | 24.10 | a | 42.00 | |||||||||
1991 | 28.43 | a | 35.29 | 30.50 | a | 37.40 | 43.58 | 48.74 | c | 59.81 | 60.27 | a | 54.34 | a | 46.35 | 35.73 | 32.74 | 42.77 | ||||||||
1992 | 29.37 | a | 34.82 | a | 36.68 | 42.97 | 48.59 | d | 51.73 | 58.30 | a | 59.58 | 52.80 | 45.90 | 32.80 | 29.13 | 43.56 | |||||||||
1993 | 32.77 | 33.30 | a | 36.07 | a | 39.97 | a | 47.77 | 53.61 | b | 58.00 | 58.31 | b | 51.15 | c | 43.52 | 32.80 | 28.71 | 43.00 | |||||||
1994 | 29.14 | b | 28.15 | a | 36.45 | b | 38.08 | e | 44.57 | a | 56.17 | a | 59.65 | 61.27 | a | 54.31 | a | 40.74 | 30.45 | a | 31.58 | 42.55 | ||||
1995 | 29.77 | a | 35.81 | b | 34.90 | 36.07 | 42.21 | b | 50.69 | d | 58.26 | 61.61 | 54.38 | d | 43.53 | a | 38.73 | d | 30.76 | b | 43.06 | |||||
1996 | 28.48 | 35.14 | 33.45 | 40.11 | b | 47.90 | a | 56.80 | 61.90 | 59.67 | a | 51.33 | 43.31 | b | 34.85 | d | 30.73 | a | 43.64 | |||||||
1997 | 28.19 | 29.56 | a | 35.23 | a | 38.27 | 49.52 | 52.03 | 58.45 | 60.26 | 56.90 | 41.71 | 35.77 | 27.87 | a | 42.81 | ||||||||||
1998 | 30.58 | 27.46 | 31.90 | 34.86 | a | 42.39 | c | 48.82 | b | 60.47 | a | 60.45 | 54.37 | 42.76 | b | 34.78 | c | 29.65 | 41.54 | |||||||
1999 | 30.60 | a | 31.25 | 34.24 | b | 34.78 | c | 45.19 | d | 53.04 | c | 59.65 | e | 58.81 | d | 52.96 | b | 43.77 | 38.11 | b | 28.58 | 42.58 | ||||
2000 | 30.03 | b | 32.58 | e | 33.06 | 41.17 | a | 49.77 | a | 56.69 | a | 61.18 | c | 61.37 | d | 56.96 | d | 43.92 | e | 29.16 | e | 32.30 | d | 44.02 | ||
2001 | 28.32 | c | 30.19 | b | 36.31 | b | 39.34 | a | 49.85 | d | 54.33 | c | 61.00 | a | 59.36 | f | 54.29 | m | 45.21 | c | 34.94 | m | ----- | z | 43.07 | d |
2002 | ----- | z | 32.92 | o | 33.21 | b | 43.20 | e | 44.29 | c | 56.30 | 62.87 | 58.59 | d | 54.29 | b | 43.25 | c | 36.59 | c | 28.23 | a | 46.08 | b | ||
2003 | 35.23 | 31.89 | a | 33.45 | 36.92 | f | 48.39 | c | 53.41 | a | 63.07 | c | 61.46 | c | 55.77 | d | 49.19 | e | 35.33 | 28.76 | f | 46.72 | b | |||
2004 | 30.37 | a | 27.76 | 38.93 | a | 38.00 | a | 46.33 | d | 53.79 | a | 58.10 | b | 57.69 | b | 52.92 | d | 42.61 | h | 34.00 | f | 30.73 | a | 43.46 | b | |
2005 | 32.61 | 33.89 | 33.41 | b | 37.79 | b | 48.03 | 51.79 | b | 60.43 | a | 59.26 | 53.52 | c | 45.52 | b | 37.03 | a | 30.76 | b | 43.67 | |||||
2006 | 29.76 | n | 32.56 | a | 31.60 | a | 39.71 | b | 49.26 | 57.53 | 62.90 | 59.74 | 51.86 | b | ----- | z | 36.54 | d | 28.52 | d | 45.02 | b | ||||
2007 | 26.31 | b | 30.53 | i | 35.83 | a | 39.15 | c | 48.32 | i | 54.93 | b | 62.45 | b | 62.30 | d | 54.69 | a | 45.03 | b | 40.33 | 27.50 | e | 44.85 | b | |
2008 | 25.38 | e | 29.82 | a | 33.53 | a | 38.32 | b | 42.07 | a | 53.00 | a | 61.82 | c | 60.10 | a | 53.86 | a | 44.25 | c | 38.62 | a | 29.89 | c | 42.56 | |
2009 | 32.34 | b | 31.57 | e | 34.15 | e | 37.03 | a | 50.70 | a | 53.11 | b | 62.17 | a | 58.35 | 54.58 | d | 40.67 | a | ----- | z | 25.65 | h | 45.47 | b | |
2010 | 30.23 | e | 30.68 | c | 31.97 | ----- | z | 43.28 | b | 53.54 | b | 62.39 | 61.10 | b | 54.26 | c | 46.06 | 32.83 | 32.85 | d | 43.56 | a | ||||
2011 | 27.11 | c | 26.88 | b | 35.14 | c | 39.73 | 43.75 | c | 52.43 | 61.29 | 61.87 | 55.07 | 43.87 | 34.83 | 27.74 | 42.48 | |||||||||
2012 | 31.06 | 30.45 | 32.77 | 41.30 | 47.22 | d | 58.19 | i | 61.61 | 61.61 | 55.03 | 44.17 | b | 37.57 | 29.13 | 42.90 | a | |||||||||
2013 | 26.61 | 27.14 | 36.58 | 40.10 | 46.80 | a | 56.47 | 62.32 | 60.77 | 54.50 | 40.94 | 37.30 | 28.68 | 43.18 | ||||||||||||
2014 | 32.42 | 33.19 | a | 36.27 | a | 40.04 | e | 44.68 | l | 56.13 | 62.39 | 58.23 | 56.33 | 47.97 | 37.50 | 33.13 | 44.87 | a | ||||||||
2015 | 33.06 | 35.82 | 39.29 | 39.77 | 45.42 | 57.10 | 59.13 | 61.45 | 56.30 | 48.55 | 33.27 | 32.21 | q | 46.29 | a | |||||||||||
Period of Record Statistics | ||||||||||||||||||||||||||
MEAN | 28.07 | 29.32 | 32.92 | 38.03 | 44.91 | 52.46 | 59.36 | 58.48 | 52.67 | 43.01 | 34.35 | 29.35 | 42.05 | |||||||||||||
S.D. | 3.44 | 3.79 | 2.76 | 2.60 | 2.62 | 2.69 | 1.89 | 1.89 | 2.32 | 2.96 | 2.72 | 2.47 | 1.25 | |||||||||||||
SKEW | -1.07 | -0.52 | -0.14 | -0.09 | 0.05 | -0.22 | -0.07 | -0.11 | -0.68 | -1.03 | -0.60 | -0.31 | -0.51 | |||||||||||||
MAX | 35.23 | 35.82 | 39.29 | 44.27 | 50.70 | 57.53 | 63.07 | 62.30 | 56.96 | 49.19 | 40.33 | 34.31 | 44.02 | |||||||||||||
MIN | 13.87 | 18.88 | 26.81 | 32.03 | 39.22 | 46.31 | 55.13 | 54.34 | 44.90 | 30.59 | 25.28 | 23.32 | 39.43 | |||||||||||||
YRS | 63 | 64 | 70 | 73 | 71 | 75 | 77 | 73 | 74 | 69 | 66 | 55 | 31 |