SUDBURY -- Environment Canada issued a frost advisory Monday, as mid-September temperatures are expected to reach near the freezing mark overnight.

The advisory covers Greater Sudbury, Sault Ste. Marie, St. Joseph Island, Searchmont, Montreal River Harbour, Batchawana Bay, Agawa, Lake Superior Park, North Bay, Powassan, Mattawa, West Nipissing, French River, Timmins, Cochrane, Iroquois Falls, Little Abitibi, Kesagami Lake, Blind River, Thessalon, Espanola, Killarney, Kirkland Lake, Englehart, Temiskaming Shores, Temagami, Kapuskasing, Hearst, Smooth Rock Falls, Fraserdale, Pledger Lake, Elliot Lake, Ranger Lake, Chapleau, Missinaibi Lake, Gogama and Foleyet.

"Frost may damage some crops in frost-prone areas," the advisory said. "Patchy frost is likely tonight into Tuesday morning across portions of northeastern and central Ontario."

Cover up plants, especially those in frost-prone areas. Take preventative measures to protect frost-sensitive plants and trees.