| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1971 | ----- | z | ----- | z | ----- | z | ----- | z | 51.23 | t | 55.25 | 57.13 | 61.50 | 59.57 | 52.50 | 47.80 | 41.37 | 53.59 | ||||||||
| 1972 | 40.97 | 45.95 | 47.80 | a | 46.57 | 53.03 | 57.35 | 61.15 | 60.87 | 57.80 | 52.95 | 48.95 | 40.34 | 51.14 | ||||||||||||
| 1973 | 41.77 | c | 48.62 | 46.05 | 50.28 | 53.39 | 57.48 | 59.10 | 58.34 | 60.82 | 53.76 | 46.48 | b | 46.71 | 51.90 | |||||||||||
| 1974 | 40.90 | 44.32 | 47.35 | 49.45 | 52.42 | 55.93 | 59.79 | 60.60 | 60.62 | 54.58 | 49.37 | 45.15 | 51.71 | |||||||||||||
| 1975 | 44.85 | 44.68 | 45.94 | 45.97 | 53.39 | 55.97 | a | 59.97 | 58.97 | 59.95 | 53.40 | b | 46.52 | 45.05 | a | 51.22 | ||||||||||
| 1976 | 44.55 | 43.21 | 45.39 | 47.65 | 53.23 | 55.44 | c | 60.87 | 61.02 | 61.43 | 56.24 | 51.33 | 44.24 | 52.05 | ||||||||||||
| 1977 | 44.63 | 49.75 | 45.85 | 51.23 | 51.84 | 57.73 | 59.77 | 62.23 | 58.78 | 55.69 | 47.35 | 46.87 | 52.64 | |||||||||||||
| 1978 | 46.61 | 47.02 | 49.47 | 49.72 | 53.63 | 59.28 | 59.58 | 60.18 | 58.78 | 54.97 | 43.33 | 38.19 | 51.73 | |||||||||||||
| 1979 | 37.84 | 43.80 | 48.10 | 49.58 | 53.85 | 55.75 | 61.19 | 61.29 | 62.53 | 56.00 | 47.32 | 47.52 | c | 52.06 | ||||||||||||
| 1980 | 41.29 | 47.71 | 45.81 | 49.33 | 52.68 | 56.32 | 59.34 | 56.79 | 57.98 | 54.97 | 49.82 | 47.02 | 51.59 | |||||||||||||
| 1981 | 48.29 | 46.96 | 47.66 | 50.18 | 53.40 | 58.02 | 58.74 | 60.15 | 58.15 | 52.21 | 48.07 | 46.16 | 52.33 | |||||||||||||
| 1982 | 40.69 | 43.75 | 44.63 | 46.22 | 51.65 | 55.42 | 58.53 | 59.23 | 58.80 | 55.55 | 46.58 | 44.69 | 50.48 | |||||||||||||
| 1983 | 47.06 | 48.36 | 50.52 | 50.35 | 54.53 | 57.48 | 61.16 | 61.18 | 59.40 | 54.73 | 49.42 | 42.53 | 53.06 | |||||||||||||
| 1984 | 45.53 | 47.40 | 49.90 | 48.98 | 53.18 | 55.10 | 57.45 | 60.89 | 59.35 | 52.65 | 47.33 | 41.19 | 51.58 | |||||||||||||
| 1985 | 43.18 | 42.84 | 43.95 | 49.55 | 53.37 | 57.20 | 59.44 | 59.53 | 57.15 | 52.27 | 41.48 | 42.55 | 50.21 | |||||||||||||
| 1986 | 47.79 | 47.39 | 51.29 | 48.67 | 53.06 | 58.32 | 58.74 | 58.29 | 55.72 | 54.00 | 49.17 | 44.65 | 52.26 | |||||||||||||
| 1987 | 44.60 | 46.62 | 49.00 | 51.57 | 55.65 | 56.58 | 58.55 | 58.82 | 57.67 | 56.00 | 49.97 | 41.81 | 52.24 | |||||||||||||
| 1988 | 43.06 | 47.00 | 46.89 | 50.25 | 53.45 | 56.33 | 59.24 | 57.94 | 57.58 | 56.68 | 48.80 | 44.60 | 51.82 | |||||||||||||
| 1989 | 43.98 | 39.95 | 47.27 | 54.00 | 54.37 | 59.10 | 60.35 | 60.85 | 59.08 | 53.69 | 48.98 | 45.23 | 52.24 | |||||||||||||
| 1990 | 45.39 | 44.04 | 49.13 | 51.92 | 53.60 | a | 58.00 | 60.45 | 62.06 | 62.30 | 53.16 | 48.58 | 38.44 | 52.26 | ||||||||||||
| 1991 | 43.26 | 50.96 | 46.00 | 49.25 | 51.94 | 55.70 | 60.02 | 61.47 | 63.02 | 56.34 | i | 49.85 | 45.21 | 52.42 | ||||||||||||
| 1992 | 46.63 | 51.55 | 51.66 | 54.75 | 57.58 | 59.70 | j | 62.19 | 61.94 | 58.87 | 55.60 | 48.80 | 42.58 | 53.83 | ||||||||||||
| 1993 | 41.39 | 44.91 | 50.60 | 51.45 | 57.24 | 59.37 | 60.15 | 61.82 | 58.28 | 55.74 | 44.38 | 44.29 | 52.47 | |||||||||||||
| 1994 | 46.82 | 44.41 | 49.29 | 51.98 | 55.53 | 57.03 | 59.66 | 63.68 | 61.70 | 53.68 | 43.70 | 43.84 | 52.61 | |||||||||||||
| 1995 | 47.53 | 49.75 | 48.61 | 50.65 | 55.38 | n | 59.03 | j | 62.42 | 61.75 | q | 62.50 | l | 54.52 | 52.00 | 48.92 | s | 52.21 | ||||||||
| 1996 | 45.37 | 46.78 | 49.39 | 51.15 | t | 54.33 | y | 58.05 | i | 60.81 | 60.63 | p | 59.73 | 54.66 | 49.20 | 45.77 | 51.46 | |||||||||
| 1997 | 44.61 | 46.82 | 47.84 | 51.70 | 59.14 | q | ----- | z | 61.38 | r | 64.53 | l | 63.76 | i | 54.45 | 51.83 | l | 44.84 | l | 49.08 | ||||||
| 1998 | 46.97 | m | 47.23 | 48.14 | i | 49.58 | 54.03 | o | 60.13 | k | 65.69 | o | 63.33 | v | 57.81 | v | 53.73 | 47.88 | 43.28 | a | 48.34 | |||||
| 1999 | 42.90 | f | 43.93 | n | 45.56 | e | 48.79 | p | 51.23 | p | 57.13 | c | 57.57 | a | 60.86 | j | 57.83 | j | 50.80 | f | 49.95 | h | 45.14 | m | 53.42 | |
| 2000 | 41.14 | i | 47.29 | h | 44.66 | f | 48.26 | i | 53.70 | c | 56.77 | h | 56.72 | o | 56.71 | n | 58.62 | j | 52.90 | g | 45.58 | q | 44.76 | f | 53.70 | |
| 2001 | 44.76 | d | 43.45 | f | 45.34 | b | 45.86 | e | 53.93 | i | 50.58 | j | 55.79 | g | 57.25 | i | 57.08 | l | 51.73 | e | 49.54 | c | 44.61 | c | 46.97 | |
| 2002 | 42.31 | g | 38.45 | f | 44.18 | a | 49.50 | c | 52.07 | d | 56.84 | k | 61.42 | g | 61.09 | h | 58.55 | k | 52.40 | f | 42.09 | a | 47.78 | d | 47.12 | |
| 2003 | 49.30 | h | 45.50 | d | 50.45 | j | 49.85 | g | 53.21 | e | 58.20 | h | 61.66 | i | 62.26 | j | 60.02 | e | 56.25 | k | 46.06 | e | 45.09 | d | 49.98 | |
| 2004 | 46.17 | d | 46.67 | b | 49.58 | g | 53.83 | d | 56.23 | i | 59.79 | k | 63.92 | l | 64.46 | f | 59.89 | k | 54.69 | 47.30 | 46.00 | g | 49.73 | |||
| 2005 | 45.25 | g | 46.86 | g | 49.95 | j | 50.43 | h | 57.58 | e | 59.22 | l | 61.67 | h | 57.68 | 54.52 | 52.88 | k | 45.58 | 43.60 | 51.79 | |||||
| 2006 | 45.31 | 43.84 | 44.15 | 48.53 | j | ----- | z | 58.62 | ----- | z | 55.98 | 56.25 | 50.79 | 47.00 | 43.03 | 49.44 | ||||||||||
| 2007 | 41.02 | 44.04 | 47.05 | a | 48.47 | a | 51.28 | d | 55.30 | e | 60.59 | c | 59.98 | f | 56.55 | 51.60 | 45.37 | 44.66 | 49.63 | |||||||
| 2008 | 39.35 | 42.39 | g | 43.03 | 47.23 | f | 54.11 | 52.43 | 56.40 | 58.18 | 55.13 | 51.73 | 49.77 | 40.00 | 50.01 | |||||||||||
| 2009 | 42.95 | 43.77 | 43.55 | 46.53 | 50.97 | 57.03 | 57.42 | 58.92 | 58.32 | 52.44 | 47.18 | 40.06 | 49.93 | |||||||||||||
| 2010 | 47.65 | 46.36 | 45.81 | 46.77 | 49.87 | 54.50 | 55.24 | 56.55 | 58.15 | 52.63 | 45.38 | 44.50 | 50.28 | |||||||||||||
| 2011 | 43.60 | 41.18 | 45.56 | 45.38 | 49.96 | d | 56.03 | 58.39 | 58.89 | 58.85 | 53.81 | 45.18 | 40.45 | 49.77 | ||||||||||||
| 2012 | 42.88 | b | 43.90 | 42.97 | 48.66 | b | 50.89 | 54.87 | 57.45 | 57.65 | 55.00 | 52.71 | 48.80 | 41.31 | 49.76 | |||||||||||
| 2013 | 40.52 | 43.20 | 45.97 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 43.23 | ||||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 43.97 | 45.84 | 46.99 | 49.58 | 53.32 | 56.65 | 59.36 | 59.79 | 58.76 | 53.90 | 47.48 | 43.63 | 51.57 | |||||||||||||
| S.D. | 2.61 | 2.59 | 2.34 | 2.35 | 1.89 | 1.56 | 1.63 | 1.90 | 2.11 | 1.51 | 2.38 | 2.47 | 0.97 | |||||||||||||
| SKEW | -0.31 | 0.12 | 0.19 | 0.14 | 0.53 | -0.28 | -0.40 | -0.15 | 0.00 | -0.04 | -0.63 | -0.43 | -0.62 | |||||||||||||
| MAX | 48.29 | 51.55 | 51.66 | 54.75 | 57.58 | 59.37 | 62.42 | 63.68 | 63.02 | 56.68 | 52.00 | 47.78 | 53.06 | |||||||||||||
| MIN | 37.84 | 39.95 | 42.97 | 45.38 | 49.87 | 52.43 | 55.24 | 55.98 | 54.52 | 50.79 | 41.48 | 38.19 | 49.76 | |||||||||||||
| NO YRS | 36 | 36 | 37 | 34 | 33 | 31 | 33 | 31 | 34 | 36 | 39 | 37 | 25 | |||||||||||||