It's a sign that cooler temperatures are in store.
Environment Canada has issued its first frost advisory of the season for Sarnia-Lambton.
The national weather agency said the temperature is expected to drop to near freezing Wednesday night and into early Thursday morning.
It said frost may damage some crops in frost-prone areas.
We're being told to cover up plants, and take preventative measures to protect frost-sensitive plants and trees.
Environment Canada issues frost advisories when temperatures are expected to reach the freezing mark during the growing season, leading to potential damage and destruction of plants and crops.
