Like most years for Iowa farmers, 2006 was a weather roller coaster ride. The graph shows the weekly departure from 30-year average degree day accumulations from May through September. One way to read the chart is to consider a 1- to 3-week time period and look at the slope of a line at that time. If it was warmer than normal, the line rises; if cooler than normal, the line falls; and if the weather is at the average, it will neither rise nor fall
