Reduced visibility expected for Ontario due to Christmas Day fog: Environment Canada

Near-zero visibility is expected to persist throughout parts of Ontario on Christmas Day due to foggy conditions.

Environment Canada issued fog advisories Monday for much of the province, starting from Windsor in the southwest to the Niagara and Kawartha Lakes areas in the northeast.

It said visibility was expected to improve in the morning, but fog may remain into the afternoon for some areas, with dense fog developing again in the evening.

"Generally not what people want to see around Christmas if they want to see a white Christmas," said Environment Canada meteorologist Ryan Rozinskis.

"But that should be the last of the really foggy nights, at least for now, because we're going to be getting into some rain tomorrow. It's a very light rain or drizzle spreading all over southern Ontario and that's going to help reduce the amount of fog."

Travel could be hazardous, weather agency warns

The agency warned travel could be hazardous due to reduced visibility and said that drivers should slow down, watch for tail lights ahead and be prepared to stop.

Fog is not unusual for this time of year, especially when there are mild conditions.

"The ground can be colder, the lakes are starting to cool down and then we have this surge of warmer, moister air," said Rozinskis.

"We also have less daylight so less potential of heating, which will also prevent fog. So basically it's a good pattern when you get warm moist air over southern Ontario in winter to start seeing fog."

In the nation's capital, children awoke to a cloudy sky and small clumps of dirt-covered ice on the ground. Ottawa is forecast to reach 4 C Monday afternoon before going down to freezing overnight.

A week ago, Environment Canada said Ottawa had the warmest Dec. 18 since record-keeping started in the city some 134 years ago, reaching 7.1 C on that date.

The mild start to the season has locals concerned about the Rideau Canal, which bills itself as the world's largest outdoor ice rink. Last year, the skateway didn't open for the first time in 53 years.

The National Capital Commission, the Crown corporation that oversees the skateway, said the Canal can only open if there are at least 10 consecutive days of temperatures between -10 C and -20 C, which typically occurs in mid-January.

In late November, The Weather Network forecasted a mild Christmas season for Ontario and Quebec, but said much colder temperatures should follow.

Up in northern Ontario, freezing rain is in the forecast for areas such as Timmins and Thunder Bay starting Monday night. It is expected to continue for most of the day on Tuesday, with upwards of 15 millimetres of ice building up on some surfaces.

In Montreal, only small traces of an early December snowstorm remained on the ground as the sun shined on Christmas morning. Environment Canada forecasted positive temperatures throughout the day, peaking at 4 C in the late afternoon and early evening.

The agency's historical weather data shows Montreal's average daily maximum December temperature was -1.4 C between 1981 and 2010.

Environment Canada showed the temperature in Fredericton on Christmas Day will reach around 3 C.

The average temperature for this time of the year is a high of -2.6 C and a low of -13.5 C. The low Christmas night is forecast to be 1 C.

Charlottetown is forecast to reach a seemingly balmy 5 C. The average high for this city is -1.5 C and the average low is -10 C at this time of the year.

The agency said Christmas in Alberta would feature sunny conditions and high temperatures hovering just above 0 C.

 Meanwhile, a wind warning was in effect Monday morning for Metro Vancouver, where heavy rains are expected.