With an unseasonably cold arctic air mass in place across southern Ontario, temperatures will plunge to near or below the 0 C mark for several hours overnight into early Monday morning.
An advisory from Environment Canada says frost is quite likely, especially in frost prone areas where the wind can become light or calm under mainly clear skies.
Tender plants should be protected or brought indoors this evening if possible.
Temperatures will rebound quickly upwards Monday morning as the airmass moderates under the strong mid-May sun.
