Historical data is one of the best tools we have for estimating when the conditions will be right to plant. We can look at previous planting dates to have a good estimate of when to be ready, but another useful piece of information is the average date on which the last frost occurs in your area.
The map below shows the 10-year average of the last spring frost date across the U.S., which we computed using data from over 50,000 weather stations.
Based on this data, we can see that in a number of southern states, such as Texas, Arkansas and Mississippi, for example, there is typically no concerns of a frost after mid to late March. In the northern plains states, however, a frost can occur in late spring, or even in the early summer. The blank (white) locations in the map above indicate that there was no frost at all in at least 5 years from 2009 to 2018.
What to remember about frost damage in corn and soybeans
Corn generally keeps its growing point below ground until it reaches the 5-leaf collar stage, so it is somewhat protected from above ground frost. However, if temperatures stay below 28 degrees F for more than a few hours, even the growing point that is protected by soil can be damaged. Soybeans are more susceptible to frost damage because their growing point emerges as soon as the crop does.
The most important thing to do if your crop gets hit by a late frost is to give it a few days to see if the crop can recover. As long as the growing point survives, you may lose some leaves, but your crop may maintain its yield potential.