Those who have started their spring planting may want to cover up their gardens Friday night.
Environment Canada issued a frost advisory Friday afternoon for the majority of southern Ontario including: Windsor-Essex, Chatham-Kent, Sarnia-Lambton, London-Middlesex, Elgin County and Oxford County, along with Huron-Perth and Grey-Bruce counties.
Temperatures across the region are expected to hover around zero overnight and in some areas, it will fall below -1 C.
On the eve of May 1, the average overnight low for this time of year hovers around 4 C.
In order to protect frost-sensitive plants and trees from potential damage, they should be covered with a blanket or burlap. Hanging or potted plants can be tucked away in sheds or brought inside houses.
The frost advisory was ended on Saturday morning, with temperatures expected to warm up throughout the weekend.