Environment Canada issued a frost advisory for Huron Perth on Sunday.
The advisory is in effect for Wingham - Blyth- Northern Huron County, Goderich - Bluewater - Southern Huron County, Listowel - Milverton - Northern Perth County and Stratford - Mitchell - Southern Perth County.
According to the weather agency, temperatures are expected to fall to near the freezing mark overnight Sunday.
Frost may damage some crops in frost-prone areas and should be protected.