Lakefront Marathon - October. The Lakefront Marathon is a USA Track & Field certified course that starts in the town of Grafton. The marathon is on a scenic point-to-point course which travels south through rural countryside, quiet neighborhoods and finishes along the shores of Lake Michigan at Veteran's Park in downtown Milwaukee. The marathon starts at an elevation of 790 feet and finishes at an elevation of 545 feet. The average temperature on race day is 54 °F, with an average low of 43 °F and an average high of 64 °F.