The chilliest temperatures of the season so far are forecast for Wednesday night.
Environment Canada has issued a frost advisory for Windsor-Essex and Chatham-Kent through early Thursday.
The weather agency said patchy frost is possible in some areas, with low temperatures flirting with the 0 Celcius mark.
If you still have plants outside, you may want to take steps to protect them.
"Cover up plants, especially those in frost-prone areas," read the advisory from Environment Canada. "Take preventative measures to protect frost-sensitive plants and trees."
Single-digit lows are forecast all week, though milder temperatures may be seen this weekend.