A near-perfect week! Sept.13 - 20 provided seasonally normal temperatures, bright sunshine and some light rain at week's end; all of which are favorable to Iowa's maturing crop. As of Sept. 21, the mid-range forecast is calling for night temperatures that should NOT approach killing temperatures. If this bears out, it will mean no early frost in 2009.
Iowa State University
Pope, Richard O., "Degree Days - Watching, Waiting and Staying Warm" (2009). Integrated Crop Management News. 534.