Lambton's Medical Officer of Health has issued another cold weather alert for Sarnia-Lambton.
The threshold for an alert is a low temperature of -15 C.
Residents are advised to take precautions by dressing in layers, shielding exposed areas from the cold wind like the head, neck and face and by limiting time spent outdoors.
During an alert, public health advises local agencies that provide shelter and assistance to the homeless to prepare for an increase in demand.
The alert is expected to only be in effect for tonight with temperatures expected to start trending higher.
A high of 9 C (48 F) is forecast for Friday.
