NATIONAL ARBORETUM DC, MARYLAND

Monthly Average Minimum Temperature (Degrees Fahrenheit)

(186350)

File last updated on May 16,
*** Note *** Provisional Data *** After Year/Month 201205
a = 1 day missing, b = 2 days missing, c = 3 days, ..etc..,
z = 26 or more days missing, A = Accumulations present
Long-term means based on columns; thus, the monthly row may not
sum (or average) to the long-term annual value.
MAXIMUM ALLOWABLE NUMBER OF MISSING DAYS : 5
Individual Months not used for annual or monthly statistics if more than 5 days are missing.
Individual Years not used for annual statistics if any month in that year has more than 5 days missing.
YEAR(S) JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANN
1948 ----- z ----- z ----- z ----- z ----- z ----- z ----- z 63.48 56.43 45.97 41.90 30.77 47.71
1949 33.84 33.79 36.52 42.67 53.52 62.93 70.48 65.58 54.57 52.26 36.70 32.55 b 47.95
1950 37.25 g 30.75 31.68 f 38.81 d 52.94 60.30 64.87 62.74 56.67 47.61 35.21 a 25.89 c 47.58
1951 29.48 27.48 a 34.41 d 41.80 51.61 61.30 66.14 c 63.58 58.87 49.00 33.39 b 31.97 a 45.75
1952 32.13 32.07 35.74 47.47 53.04 f 64.28 a 68.56 d 65.61 c 62.00 y 40.76 j 39.43 32.52 46.42
1953 33.29 33.11 ----- z ----- z ----- z 63.13 66.87 64.41 d 56.00 i 47.56 d 36.84 e 33.17 m 49.31
1954 26.45 i 33.29 35.71 48.73 50.71 c 62.77 d 65.48 65.45 60.83 51.26 36.43 29.96 e 49.15
1955 27.00 27.79 38.13 48.43 56.45 59.77 72.26 69.45 60.27 48.39 35.47 26.03 47.45
1956 27.20 a 32.14 33.90 42.48 a 51.32 61.77 66.87 65.29 57.47 50.42 39.31 a 37.23 47.12
1957 25.29 33.25 35.90 47.83 55.77 a 65.33 67.03 63.16 61.53 44.48 39.87 32.00 47.62
1958 25.55 22.18 32.87 44.87 53.61 60.07 68.71 64.03 56.33 46.48 40.10 23.03 44.82
1959 24.74 27.00 33.35 47.30 57.90 63.80 68.52 69.65 60.73 52.68 37.80 32.77 48.02
1960 30.68 30.66 26.16 47.87 52.42 62.13 65.16 67.52 60.20 47.45 37.67 20.48 45.70
1961 20.29 29.82 36.58 41.03 51.45 61.73 67.06 67.29 64.43 48.06 43.03 29.39 46.68
1962 26.71 27.07 34.03 46.13 57.10 63.87 65.00 65.32 56.70 49.26 35.90 23.94 45.92
1963 23.65 21.43 37.16 44.00 53.06 62.03 66.48 64.03 55.43 47.16 41.83 23.58 44.99
1964 26.29 27.76 36.68 42.87 55.13 63.00 67.52 63.84 57.47 42.26 38.97 32.71 46.21
1965 24.87 26.50 32.81 42.50 56.26 60.93 65.65 64.13 59.57 43.90 38.10 31.60 a 45.57
1966 24.68 27.89 35.19 41.93 50.81 62.07 67.48 65.77 56.50 43.19 37.07 29.68 45.19
1967 30.42 21.86 33.52 43.43 47.03 60.93 66.06 65.42 54.80 44.42 33.70 30.23 44.32
1968 22.32 24.69 35.65 43.10 51.26 61.23 67.19 67.81 57.27 50.77 41.53 29.00 45.99
1969 26.42 29.14 32.16 45.10 52.48 63.83 68.71 64.58 57.73 45.39 36.50 28.61 45.89
1970 20.71 27.18 32.45 42.87 54.65 61.60 66.19 66.16 62.17 51.71 39.60 30.06 46.28
1971 23.10 29.61 32.03 38.77 50.35 63.77 65.32 63.90 61.30 54.61 37.63 35.77 46.35
1972 29.81 26.00 34.81 41.13 51.94 59.33 67.16 63.61 59.53 43.71 36.53 34.71 45.69
1973 27.42 24.96 37.81 e 44.30 50.32 66.27 67.52 68.26 60.97 48.19 39.03 31.19 47.19
1974 31.52 25.04 35.26 45.00 53.39 60.20 66.45 67.39 58.17 41.81 38.34 a 30.84 46.12
1975 28.52 29.96 31.80 a 40.27 56.68 63.83 65.81 66.87 57.03 50.19 39.43 29.61 46.67
1976 22.03 31.82 a 36.45 45.27 50.52 64.83 65.32 63.42 56.37 42.87 31.30 22.68 44.41
1977 15.74 26.36 39.58 45.40 54.87 60.07 68.13 a 67.52 62.45 a 44.74 41.93 27.38 b 46.18
1978 20.90 20.32 32.29 43.43 53.10 62.53 65.87 a 69.67 a 59.77 43.10 38.90 29.10 44.91
1979 23.06 16.00 34.67 a 44.87 54.13 58.77 66.00 65.52 58.17 45.63 a 39.23 30.90 44.75
1980 26.29 22.33 b ----- z 44.80 54.19 59.77 67.97 67.32 60.57 45.06 33.93 a 26.65 46.26
1981 20.32 27.36 32.03 45.47 51.19 63.97 67.35 62.45 57.68 b 42.46 c 37.64 b 27.87 44.65
1982 17.19 27.14 33.52 39.37 55.03 61.40 67.06 61.06 56.03 45.16 37.30 34.35 44.55
1983 28.35 26.00 37.06 41.90 52.23 61.77 65.77 65.55 54.73 45.19 35.20 25.32 44.92
1984 19.10 31.45 29.55 43.33 51.19 61.67 64.32 64.29 52.00 51.73 a 31.20 32.52 44.36
1985 19.87 25.75 34.42 45.50 53.81 59.73 64.97 63.48 55.07 46.16 42.13 22.97 44.49
1986 23.06 25.04 32.10 42.33 52.55 60.63 66.77 61.35 55.60 44.94 32.73 26.65 43.65
1987 22.13 22.04 33.90 40.50 51.13 61.30 67.13 64.06 57.40 36.71 34.73 30.19 43.44
1988 16.39 25.28 33.48 41.67 51.87 59.43 66.45 65.29 50.97 35.29 31.43 20.61 41.51
1989 24.52 ----- z 41.57 x 40.27 50.45 62.63 64.03 60.81 52.27 38.94 ----- z 18.35 45.81
1990 31.81 32.18 37.19 42.93 52.35 60.37 68.26 65.45 56.93 48.48 37.53 32.71 47.18
1991 27.16 30.54 38.13 46.87 60.32 63.87 70.19 68.10 58.70 47.06 37.60 32.26 48.40
1992 28.19 30.93 35.06 43.87 50.35 59.73 68.23 61.94 57.67 41.87 38.60 30.84 45.61
1993 30.16 23.86 32.03 43.10 55.52 61.87 70.42 66.39 59.40 44.71 35.37 28.32 45.93
1994 18.84 25.29 32.52 46.67 48.74 65.70 69.84 63.10 55.17 41.39 39.43 31.74 44.87
1995 29.45 i 22.57 36.58 39.67 52.87 62.90 69.03 67.55 ----- z ----- z ----- z ----- z 50.17
1996 22.65 27.00 30.35 43.37 52.29 64.57 66.61 64.39 59.13 44.87 32.40 32.39 45.00
1997 24.68 32.00 35.84 41.17 48.52 60.47 67.13 64.03 56.57 44.42 34.80 29.39 44.92
1998 33.00 31.39 35.81 45.97 57.52 64.53 67.55 66.74 62.20 47.13 35.23 32.97 48.34
1999 26.06 27.14 32.00 43.63 53.74 63.73 71.52 66.94 58.43 43.06 39.97 29.52 46.31
2000 23.68 28.66 37.94 43.77 54.58 63.80 63.61 64.52 56.83 45.74 33.20 20.90 b 44.77
2001 23.03 28.36 31.68 44.07 53.87 65.00 64.32 68.48 55.73 43.61 36.50 b ----- z 46.79
2002 ----- z ----- z ----- z ----- z ----- z ----- z ----- z ----- z ----- z ----- z ----- z 28.60 a 28.60
2003 23.52 25.14 35.06 44.00 53.77 63.20 68.84 69.74 60.90 45.77 42.43 30.06 46.87
2004 21.55 26.93 36.65 46.53 61.32 63.97 69.61 67.23 61.70 47.55 40.97 29.77 47.81
2005 27.87 29.18 33.94 45.83 50.97 67.31 n 71.00 70.48 62.57 51.29 40.07 27.39 46.42
2006 32.72 f 29.11 36.71 47.47 53.65 64.23 71.19 70.00 58.83 46.35 40.77 33.42 50.16
2007 31.71 21.79 35.87 a 42.27 56.35 65.13 68.13 69.29 61.13 53.58 38.23 31.65 47.93
2008 28.26 29.41 35.84 46.57 52.29 65.83 69.10 64.90 61.53 46.23 38.60 31.19 47.48
2009 23.87 30.04 36.19 49.23 59.45 69.03 67.90 69.48 59.50 46.52 41.53 28.81 48.46
2010 25.10 25.64 40.16 47.97 57.26 69.33 71.90 69.42 61.50 49.65 37.92 f 25.90 49.44
2011 23.03 28.85 a 34.93 a 48.14 a 57.74 66.80 72.55 68.13 a 64.65 d 47.00 c 40.07 a 32.48 b 48.70
2012 28.65 32.14 a 43.52 45.96 b 57.40 u ----- z ----- z ----- z ----- z ----- z ----- z ----- z 37.57
Period of Record Statistics
MEAN 25.38 27.54 34.81 44.09 53.46 62.70 67.49 65.75 58.35 46.27 37.64 29.21 45.96
S.D. 4.32 3.70 2.75 2.63 2.87 2.29 2.11 2.42 2.91 3.79 2.99 3.96 1.49
SKEW -0.06 -0.52 0.01 -0.04 0.51 0.62 0.53 0.10 -0.15 -0.26 -0.35 -0.75 -0.19
MAX 33.84 33.79 43.52 49.23 61.32 69.33 72.55 70.48 64.65 54.61 43.03 37.23 48.70
MIN 15.74 16.00 26.16 38.77 47.03 58.77 63.61 60.81 50.97 35.29 31.20 18.35 41.51
NO YRS 59 62 59 62 60 61 62 63 60 61 60 61 51