A cold weather alert issued medical officer of health for Windsor-Essex will remain in effect until Saturday.
Temperatures fell to -18 C early Friday morning but were expected to rise throughout the day.
"With these freezing weather conditions upon us, area residents need to protect themselves," Dr. Allen Heimann wrote in a release.
Heimann warned that frostbite and hypothermia are the most common problems that can happen with extremely cold weather.
"Individuals who are stranded and those without shelter are in immediate danger, as are individuals whose homes are poorly insulated or without heat," Heimann wrote.
Heimann suggested people prepare for the cold by:
- preparing a home survival kit including food, water, and an alternative source of heat
- keeping a survival kit in your vehicle that includes food, water, first aid kit
- when outside cover exposed skin, wear hats, scarves, mittens, and extra layers
- people with high blood pressure or heart disease should avoid strenuous outdoor activities because the cold puts an extra strain on the heart
Pets are also at risk, according to Melanie Coulter of the Humane Society.
"One of the things that we warn people about is one of the places cats like to go to stay warm: inside car engines," Coulter said. "So that actually is something that we do hear about pretty regularly."
Coulter suggests people bang on their hood or honk their horn before starting their vehicle.
She also said outdoor pets should have adequate food, water and protection from the elements.