For the first week of August, Wednesday was a very cool day with a number of locations unable to reach a high temperature of 70°F. One such location was Waterloo with a high of just 69°F. The featured chart looks into the accumulated frequency by fall season date for the first sub threshold daily high temperature. The algorithm considers any post 1 July date as the "fall season", but starts the plot on 1 August. For the sub 70°F threshold, yesterday's value comes in around the 10th percentile. Rewording, about one in ten years have seen such a cool high by the 5th of August. Some selected lower thresholds are plotted as well with sub 65°F having a much lower accumulated frequency until about the last week of August. We are still squarely within the summer season for Iowa, so these respites from the heat should be enjoyed!