Ontario's thick blanket of fog has a mild weather perk attached

Widespread dense fog developed through the overnight hours on Wednesday, prompting a fog advisory for most of southern Ontario urging drivers to adjust to the tricky travel conditions and reduced visibility.

"Persistent fog with visibility near zero is forming in some areas and will continue through the early morning hours," says Environment and Climate Change Canada (ECCC) in the advisory.

Visibility of less than 200 metres has been reported for some areas, including Toronto's Pearson airport, where flights should be monitored for any delays.

Freezing fog was also reported in London early Thursday.

RELATED: It’s not your imagination—here’s why fall is the foggiest season

"Clear skies and an incoming milder air mass are to blame for the dense fog that has spread into the region," says Kelly Sonnenburg, a meteorologist at The Weather Network.

The fog is forecast to stick around through the morning commute before mixing out and dissipating later in the morning.

Despite the travel issues it may cause, this round of fog is actually a signal of a very pleasant day ahead.

"The fog will make way for milder temperatures Thursday afternoon, with daytime highs climbing into the double digits for some in southwestern Ontario and several degrees above seasonal for others," Sonnenburg adds.

MUST SEE: Don't call it a comeback, Canada: Winter hasn't even started

Milder temperatures will dominate through the weekend as well, though with a period of rain showers that will quickly track across southern Ontario early Friday. Abundant sunshine, windy and mild conditions all return for Saturday.

A more consistently cold pattern isn't expected until after December 5.