Table 39. Monthly and annual averages and extremes of hourly wet bulb temperatures for CFA(a). Monthly Values Highest Lowest Five-Minute Extreme Values Average Average Average Maximum Minimum (deg F.) (deg F.) (deg F.) (deg F.) (deg F.) January 15.3 23.7 6.2 47.9 -30.3 February 18.7 28.1 7.0 48.2 -31.3 March 29.2 32.6 21.7 50.9 -17.7 April 35.5 39.1 30.0 56.0 4.8 May 42.6 47.2 38.1 66.0 8.8 June 48.3 51.5 45.5 66.2 19.8 July 52.9 55.7 49.8 67.4 24.2 August 50.9 55.6 48.0 65.6 21.3 September 44.5 50.9 40.3 65.6 11.3 October 35.8 42.4 21.9 57.2 -9.1 November 25.9 31.1 18.8 52.1 -23.5 December 17.0 23.4 8.9 46.8 -30.6 ANNUAL 35.1 38.1 32.0 67.4 -31.3 a. Data period of record spans January 1994 through December 2022.