NATIONAL ARBORETUM DC, MARYLAND

Period of Record General Climate Summary - Cooling Degree Days

From Year=1948 To Year=2012
Station:(186350) NATIONAL ARBORETUM DC
Averages Daily Extremes
Cooling Degree Days for Selected Base Temperature (F)
Base Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Annual
55 2 4 28 117 318 563 717 668 438 152 35 5 3045
57 1 2 19 89 264 503 655 606 380 115 23 3 2660
60 0 1 10 57 190 414 562 513 296 71 11 1 2128
65 0 0 3 23 95 271 407 359 173 26 3 0 1361
70 0 0 1 7 37 149 255 213 81 7 0 0 751
Cooling Degree Day units are computed as the difference between the daily average temperature and the base temperature. (Daily Ave. Temp. - Base Temp.) One unit is accumulated for each degree Fahrenheit the average temperature is above the base temperature. Negative numbers are discarded. Example: If the days high temperature was 95 and the low temperature was 51, the base 60 heating degree day units is ((95 + 51) / 2) - 60 = 13. This is done for each day of the month and summed.
Table updated on May 22,
Months with 5 or more missing days are not considered
Years with 1 or more missing months are not considered

Southeast Regional Climate Center, SERCC Webmaster