Actual air temperatures will be in the mid to upper teens, the weather service said.
Temperatures will slowly rise to above freezing around midday.
The weather service advises that those venturing out in the early morning hours wear several layers of clothing. Heads, hands and feet should be covered to prevent frostbite.
Schoolchildren should not be exposed to the cold for a prolonged period of time, and pets should be kept indoors, the weather service said.
Exposed pipes could freeze.