The coldest temperatures of the season will be settling into the state this evening. High pressure over the Dakotas will reach eastern Iowa by daybreak Saturday and continue to spill cooler temperatures into Iowa in the process. This will allow temperatures across much of Iowa to dip into the upper 20’s to lower 30’s by daybreak Saturday. These conditions will produce frost and freezing conditions which will end the growing season in many areas.
A freeze warning will go into effect early Saturday morning. Temperatures should dip below freezing during the early morning hours Saturday and remain so until just after sunrise. Temperatures below freezing for multiple hours will kill domestic outdoor plants and unattended commercial vegetation. A freeze warning means sub-freezing temperatures are imminent or highly likely. Sensitive plants should be protected or brought indoors if a longer growing season is desired.
Across central Iowa, where temperatures will be near freezing, a frost advisory will be in effect. Temperatures may dip into the lower 30’s early Saturday morning. Areas of frost are expected to form early Saturday morning. These conditions will likely damage or kill sensitive vegetation that has been left unprotected. A frost advisory means that frost is possible. Sensitive plants should be protected or brought indoors if a longer growing season is desired.