Table 18. Monthly and annual average and extreme heating degree days (HDD) for CFA(a). Daily Extremes Average Highest Lowest Highest Lowest (HDD) (HDD) (HDD) (HDD) (HDD) January 1,508 1,828 1,086 85 22 February 1,232 1,623 865 88 20 March 1,025 1,446 728 71 10 April 685 889 471 44 2 May 417 623 206 35 0 June 173 305 38 26 0 July 25 192 0 16 0 August 46 192 0 20 0 September 265 493 100 36 0 October 654 955 433 55 0 November 1,059 1,342 830 74 8 December 1,437 1,799 1,031 93 18 ANNUAL 8,524 10,268 7,421 93 0 a. Data period of record spans January 1950 through December 2025.