A moist and humid air mass combined with light winds allowed extensive fog to form across parts of southern Manitoba and southwestern Quebec.
Environment Canada issued a special weather statement for parts of southern Ontario as well, warning of near zero visibility in places like Ottawa, Petawawa, Borden and the Greater Toronto Area.
"A warm front is moving into the region and when that warm air crosses over the Great Lakes and meets with the cooler air, it results in fog," explains Brian Dillon, a meteorologist at The Weather Network.
Motorists are urged to slow down and adjust their driving habits accordingly. Those with air travel plans are also encouraged to call ahead to check the status of their flight. The fog may result in delays or cancellations.
"The fog will burn off throughout the day as temperatures begin to rise," says Dillon.
Some places in southern Ontario could see the potential for thunderstorms later in the day on Wednesday.