A very cold airmass has settled across much of southern Ontario again.
The Cold Weather Alert issued yesterday by Lambton Public Health remains in effect for Sarnia-Lambton.
The threshold for the alert is -15 C and the temperature is forecast to drop to -17 C (1F) tonight.
Environment Canada issued Extreme Cold Warnings for points east and north including London-Middlesex and Huron-Perth.
The warnings, issued when wind chills near minus 30 C are expected, ended this morning.
Residents are reminded to dress appropriately and limit exposure outdoors to avoid hypothermia and frost bite.