Normal, IL Weather OverviewScoresFors & AgainstsWeatherPhotos Average Temperature Jan 30 °F-1 °C Feb 31 °F-1 °C Mar 43 °F6 °C Apr 56 °F14 °C May 70 °F21 °C Jun 77 °F25 °C Jul 82 °F28 °C Aug 79 °F26 °C Sep 77 °F25 °C Oct 61 °F16 °C Nov 40 °F5 °C Dec 41 °F5 °C Humidity Jan 78% Feb 77% Mar 69% Apr 72% May 79% Jun 82% Jul 82% Aug 82% Sep 82% Oct 73% Nov 77% Dec 78% Rain Jan 62mm Feb 67mm Mar 100mm Apr 63mm May 196mm Jun 97mm Jul 73mm Aug 70mm Sep 84mm Oct 69mm Nov 49mm Dec 41mm Clouds Jan 65% Feb 73% Mar 59% Apr 52% May 62% Jun 48% Jul 23% Aug 31% Sep 38% Oct 41% Nov 54% Dec 53% Air quality US AQI Jan 39 Feb 39 Mar 32 Apr 33 May 35 Jun 36 Jul 39 Aug 38 Sep 36 Oct 31 Nov 41 Dec 43 Sun Jan 2UVI Feb 3UVI Mar 4UVI Apr 5UVI May 6UVI Jun 8UVI Jul 9UVI Aug 7UVI Sep 6UVI Oct 4UVI Nov 2UVI Dec 2UVI