The beginning of the growing season has been slow to arrive to the central United States. As we move further into spring, more sites will see their last freeze. A late spring freeze can be particularly damaging if the growing season has begun and plants have emerged from the ground, which is especially true in a year like this that has been so warm during the early spring. The image below, updated daily, will keep track of both freezes (temperatures falling to 32 degrees or colder) and growing degree days (which is a measure of how far into the growing season the area has progressed). Filled circles indicate that those sites have not had a freeze in the last 14 or more days, which means that those locations would be vulnerable to a late freeze. White shading on the map indicates areas that have accumulated at least 150 growing degree days, enough for early plants to emerge.
Also, the map of the median (usual) last freeze date (32 degrees) is below:
All images are courtesy of the Midwest Regional Climate Center. To see these images and others, visit the Midwest Regional Climate Center's Climate Watch page at http://mrcc.isws.illinois.edu/cliwatch/watch.htm