Grand Rapids, MI Weather OverviewScoresFors & AgainstsWeatherPhotos Average Temperature Jan 28 °F -2 °C Feb 28 °F -3 °C Mar 37 °F 3 °C Apr 52 °F 11 °C May 63 °F 17 °C Jun 73 °F 23 °C Jul 82 °F 28 °C Aug 77 °F 25 °C Sep 70 °F 21 °C Oct 54 °F 12 °C Nov 39 °F 4 °C Dec 36 °F 2 °C Humidity Jan 74% Feb 79% Mar 70% Apr 67% May 78% Jun 79% Jul 77% Aug 75% Sep 84% Oct 79% Nov 81% Dec 81% Rain Jan 23mm Feb 46mm Mar 47mm Apr 80mm May 66mm Jun 22mm Jul 73mm Aug 69mm Sep 28mm Oct 35mm Nov 41mm Dec 52mm Clouds Jan 86% Feb 89% Mar 61% Apr 58% May 71% Jun 46% Jul 24% Aug 36% Sep 56% Oct 61% Nov 73% Dec 74% Air quality US AQI Jan 29 Feb 32 Mar 30 Apr 26 May 29 Jun 34 Jul 37 Aug 38 Sep 32 Oct 23 Nov 29 Dec 32 Sun Jan 1UVI Feb 2UVI Mar 3UVI Apr 5UVI May 5UVI Jun 7UVI Jul 8UVI Aug 7UVI Sep 5UVI Oct 3UVI Nov 2UVI Dec 1UVI