What's Ontario's winter forecast this year? Here's what you need to know

Winter is coming, but what will that look like in Ontario? Well, El Niño could bring on a milder season than usual this year.

Weather agencies like Environment and Climate Change Canada (ECCC), The Old Farmer's Almanac and The Weather Network (TWN) have released their forecasts for Canada this winter season, including Ontario.

While The Farmer's Almanac forecasts a "colder than normal" winter in southern Ontario with more precipitation and snowfall than usual, TWN foresees a milder start to the season in this region with less snow in the coming weeks before the holidays.

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The network predicts the cold could continue through January, though it will depend on what El Niño brings to the region – when the colder weather does arrive, however, the Great Lakes "will be wide open" and Ontario's usual snowy spots could see more lake-effect snow.

During ECCC's seasonal forecast on Friday, the federal weather agency predicted above-normal temperatures for parts of northern Ontario.

Environment Canada's senior climatologist, David Phillips, told CTV News Toronto that while Ontario is not yet in the dead of winter, which he says is typically the end of January, these late November and early December months serve as an "opening act" for what the winter might be like.

"We have, as they say, a long…two months before we get to the core of what a winter would be like but it doesn't all of a sudden come right on you," Phillips said in an interview Sunday. "All of those forecasts, or outlooks, are really headlining it by El Niño."

WHAT IS THE DRIVING FORCE FOR A MILDER WINTER?

While El Niño is thousands of kilometres away from the province, predicted by warm waters off the coast of South America, if it's a half-degree warmer than normal, it'll likely bring warmer than average weather to Canada for the winter, Phillips said. This past fall, Phillips said the "yo-yo conditions" seen across Canada, with milder than average temperatures followed by cooler air, were likely due to this weather phenomenon.

"We've seen that to some degree in Ontario, too. We've had some snow, but not huge amounts. We had a very warm fall, and I think that was indicative of the fact that El Niño was grabbing control of the landscape and influencing our weather," he said.

The last time Canada experienced the effects of an El Niño was in 2015 and 2016, Phillips said. At that time in Ontario, the climatologist said there were fewer cold days (when temperatures dip below - 20C) than usual across the province.

"The temperature that winter was anywhere between three and three-and-a-half-degrees warmer than normal," Phillips said, from Windsor to Thunder Bay, Ont. "That's a lot."

Snowfall is more challenging to predict for the season, as Phillips says there are competing factors – particularly in the Great Lakes area. However, the climatologist said El Nino could bring lake-effect snow later in the year.

"The other thing, too, is what you get maybe is more freezing rain, so that is the bugaboo with an El Niño. Get a warm winter; you could end up with more freezing rain events," Phillips said, adding in 1998, eastern Ontario and Quebec saw days of freezing rain (which happened to be an El Niño year).

But in terms of precipitation for the upcoming season, Phillips said the pattern for Ontario is almost undecided as there is an equal chance of it being wetter or drier than usual.

While El Niño is partially responsible for a milder winter forecast, ECCC said during its winter outlook that "human-induced climate change explains most of the observed winter warming in Canada."

The United Nations' World Meteorological Organization confirmed in a provisional report that 2023 is set to be the warmest year on record, with global temperatures rising 1.4C above pre-industrial levels.

WILL THERE BE A WHITE CHRISTMAS?

A white Christmas could be possible, according to TWN, as a "more wintry pattern" is forecasted to develop around the holidays. But Phillips says it is too early to tell.

"I don't even know on the first day of winter, the 21st of December, if it's going to be a white Christmas, because, you know, the temperatures could warm up in two days, and you could get rain rather than snow," Phillips said.

Since there are some weather patterns that are hard to predict in advance, Phillips says the cardinal rule of forecasting is to “look out the window and what you see is what you’re going to get.”

During Environment Canada’s seasonal forecast, which deals with averages, Gerald Cheng, warning preparedness meteorologist, urged to stay up-to-date on the latest winter weather alerts and other cold weather tips online “to ensure you and yours are safe this winter.”  

With files from CTVNews.ca's Megan DeLaire