Winter frost

Over the last few decades, the trend for the first frost dates has been that they are occurring later in the season when compared to the long-term behavior, Justin Glisan wrote in a blog post for the Iowa State University Extension Integrated Crop Management blog Aug. 11.

Date of Freeze 32
Date of Freeze 28

The figures above illustrate the average first freeze (32°F) and killing frost (28°F) dates across the Midwest from 1980 to 2010.

While these figures show us what the average freeze and frost dates have been, it is too early to make any predictions about dates for this year yet, Glisan said.