For Iowa State students, this is Finals week. For K-12 students, just a few weeks of school remain until summer break. So it is a good time to think about summer and present a metric to compute when the summer season begins. If you consider the summer season as the warmest consecutive 91 day period (1/4th of the year) each year, the featured chart plots the start date each year for this period for Ames. The dots are colored by the average temperature departure for this period over all years. A simple linear trend line is plotted as well. The overall average is around 7 June, which just over three weeks away, but plenty of years got started in just over week from now.