September, October, and November are transition months in Nederland as the warm days of Summer are replaced by the cooler and sometimes snowy weather of Autumn and early Winter. After a warm start on Monday, a cold front will sag southward across Colorado. As you can see in the first NOAA weather map, the front will be just south of Nederland by evening. Initially, there will not be much precipitation with this system, but temperatures will become noticeably cooler. As easterly upslope flow deepens behind this front and moisture increases, there will be better chances showers and thunderstorms on Tuesday and Wednesday, especially in the afternoon when the daytime heating is the greatest. The second NOAA weather map shows the front well to our south by Tuesday. Note that the star on these maps marks the location of Nederland.