Lambton's Medical Officer of Health has issued another cold weather alert for Sarnia-Lambton.
It's the third posting this year by the Medical Officer of Health.
Temperatures are expected to drop to -17 celsius (1 F) Tuesday night.
Lambton Public Health's Paul Buttery says overexposure to cold temperatures can lead to hypothermia and frost bite.
Residents should 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 cold weather alert is expected to remain in effect until Wednesday.