Frosty Start Early This Week as Extreme Cold Brings Intense Snow Squalls in Parts of Southern Ontario

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Get ready for a blast of Arctic air across Southern Ontario this week! A surge of polar air will cause temperatures to plummet over the weekend and into early this week.

This extreme cold is also expected to trigger a multi-day snow squall event, which could result in significant snowfall for the usual snowbelt regions.

Dangerous wind chills approaching -30°C by Monday night, combined with intense snowfall rates, will create hazardous travel conditions. The hardest-hit areas are likely to be along the Lake Huron shoreline, including Grey, Bruce, and Huron counties.

Moderate wind gusts of 40-60 km/h could lead to blowing snow, with localized blizzard-like conditions possible. Non-essential travel in these regions should be avoided, as the extreme cold could quickly turn life-threatening if you become stranded.

While exact snowfall totals remain uncertain, the cold temperatures will enhance snowfall ratios, resulting in higher-than-usual snowfall rates for the same amount of moisture. Portions of Grey and Bruce counties along the shoreline could see snowfall accumulations exceeding 50 cm.

Lake Ontario and Lake Erie may also see localized lake-effect snow starting Sunday night and continuing through Tuesday. The Niagara region and Prince Edward County could receive 25-50 cm of snow in some areas, though accumulations will be highly localized.

TIMING

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

The event will begin with light snow across Southwestern Ontario and the Golden Horseshoe on Monday evening. Lake enhancement along the Lake Huron shoreline and parts of the Western GTA and Northern Niagara region is expected.

However, it’s unclear how far these snow bands will extend inland, with some models suggesting they’ll remain close to the shoreline.

For example, high-resolution Canadian models show an intense but narrow squall near the Goderich region that doesn’t stretch far inland.

Similarly, a Lake Ontario squall may take an unusual path through Grimsby, St. Catharines, and Niagara-on-the-Lake, staying close to the shoreline.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

Overnight Sunday into Monday morning, a more stable wind direction could allow a Lake Huron squall to push farther inland, potentially affecting Kitchener, Hamilton, and Burlington.

These areas could see a few hours of heavy snow during the morning commute.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

By late Monday morning, the squall may gradually drift northward, reducing snowfall around Goderich as the wind shifts westerly. The Grey-Bruce region is likely to bear the brunt of the snow squalls at this point.

The Toronto area might see the edge of the squall by late morning, but snow intensity there remains uncertain.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

On Monday evening, a persistent squall is expected to form across the Bruce Peninsula and extend over Georgian Bay into Muskoka.

However, it may struggle to reach far inland, confining the heaviest snow to shoreline areas like Parry Sound, MacTier, and Bala. Bracebridge and Gravenhurst might avoid the worst of the snow—a welcome break after this winter’s relentless storms.

Lake Erie and Lake Ontario squalls will also intensify Monday night, with the Lake Erie squall drifting north into Port Colborne and Fort Erie.

Meanwhile, the Lake Ontario squall could impact southern Prince Edward County. Unfortunately, these squalls are unlikely to shift much overnight, meaning sustained snowfall and high winds could create treacherous conditions.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

As Tuesday morning approaches, the Lake Huron squall may refocus on southern Bruce County, including Owen Sound, Sauble Beach, Kincardine, and Hanover. These areas could face significant snowfall throughout the day.

The Lake Erie squall may drift southward, offering some relief to the Niagara region, though Fort Erie could remain under heavy snow. For Prince Edward County, the Lake Ontario squall may persist through much of Tuesday, delivering relentless snowfall.

A wind shift late Tuesday should end snow squalls off Lakes Erie and Ontario, but activity off Lake Huron may reposition toward the Bruce Peninsula and Muskoka.

Details for snow squall activity beyond Tuesday night will be covered in future updates.

THE BIG CHILL

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The big factor fueling these squalls is the frigid air moving over the relatively warm Great Lakes.

Temperatures could drop to -20°C by Monday night, with wind chills in the -30s for many parts of Southern Ontario, including the southwest.

This dangerous combination of extreme cold and heavy snow could lead to life-threatening conditions if you get stranded outdoors.

That’s why it’s critical to avoid travel during this period and stay home whenever possible.

School bus cancellations are likely on Monday and Tuesday due to both extreme cold and snow squalls.

HOW MUCH TO EXPECT

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As always with snow squalls, their narrow and shifting nature makes forecasting totals challenging. Some areas may see just 1 cm, while others a short distance away could be buried under 50 cm.

Model data suggests that Bruce County will be hardest hit, particularly along the Bruce Peninsula, Port Elgin, Kincardine, and Point Clark, where over 50 cm of snow is possible.

Huron and Grey counties, including Owen Sound, Chatsworth, Hanover, Wingham, and Goderich, could see up to 50 cm in places.

Inland areas like Kitchener and Orangeville may get up to 25 cm, while the Eastern Georgian Bay shoreline, including Muskoka, could see similar totals.

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The Niagara region, especially along its northern and southern edges, may get up to 25 cm of snow between Monday night and Tuesday. In Prince Edward County, localized totals of 50 cm are possible, especially in southern areas.

Kingston could see up to 10 cm, while eastern Ontario and deep southwestern Ontario will likely receive no more than 5 cm.

Stay tuned for updates as high-resolution models refine snowfall predictions.

For now, it’s clear that this storm will bring a mix of extreme cold, heavy snow, and treacherous travel conditions to Southern Ontario. Stay safe and stay prepared!

Arctic Blast Across Canada With Potentially Coldest Air in Years; Dangerous Wind Chills Near -40°C Possible Next Week

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Get ready for a major Arctic chill as some of the coldest air in over a year is set to spread across much of Canada over the next week.

This icy blast will originate in the Arctic and surge into Central and Eastern Canada, causing temperatures to plummet to dangerously low levels. Wind chills could drop to between -30°C and -40°C—or even lower—in several regions by early next week.

This extensive polar plunge will impact much of Canada and even stretch into parts of the United States. Over the next five to seven days, nearly everyone will feel the chill in some capacity.

The Prairies will be the first to experience this frigid air as it arrives late Friday into Saturday. By early next week, the cold will spread eastward into Ontario, Quebec, and Atlantic Canada, blanketing nearly all of the country in sub-zero temperatures. The cold snap is expected to last for a few days, but relief will arrive with more seasonal air by mid to late next week.

SATURDAY

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In Alberta, Saskatchewan, and Manitoba, the cold will start to settle in Friday night and intensify into Saturday morning. Temperatures will plunge below -20°C and could approach -30°C in some areas, even before factoring in the wind chill.

The coldest conditions will hit northern areas like Fort McMurray and Thompson, where wind chills could make it feel like -40°C to -45°C.

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Most of Saskatchewan and Manitoba, excluding Winnipeg, will see wind chills between -35°C and -40°C. Winnipeg and Edmonton will feel slightly less severe, with wind chills in the low to mid -30s, while Calgary will range from -25°C to -30°C.

Northern Ontario will also begin to feel the chill, with wind chills making it feel close to -30°C in places like Thunder Bay by Saturday morning.

Meanwhile, Southern Ontario will enjoy one last relatively mild day on Saturday, with temperatures near the freezing mark. However, the arrival of the Arctic air could bring a flash freeze late Saturday in Northeastern and Southern Ontario. Rapidly dropping temperatures may lead to icy road conditions, so caution is advised.

SUNDAY

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By Sunday morning, the cold air will deepen across the Prairies, bringing wind chills into the -40s for much of Saskatchewan and Manitoba. This includes locations like Edmonton, Fort McMurray, Saskatoon, Regina, and Thompson.

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Winnipeg and Calgary will be slightly less frigid, with wind chills closer to -30°C to -35°C, though colder temperatures are expected by Monday morning.

Ontario will also see temperatures drop sharply by Sunday morning. Northern Ontario will experience bitterly cold air, with actual temperatures between -20°C and -30°C and wind chills closer to -40°C in the northernmost areas.

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Southern Ontario will see temperatures ranging from -10°C to -20°C, with the coldest air in Central and Eastern Ontario. Wind chills in Northern sections of Southern Ontario could approach -30°C, while Southwestern Ontario and the Golden Horseshoe will feel like -20°C to -25°C.

The arrival of Arctic air could also reignite lake-effect snow squalls early next week. Snowbelt regions around Lake Superior, Lake Huron, and Georgian Bay could see heavy snowfall as a result. More details on this will be provided in a separate forecast.

STAYING SAFE IN THE EXTREME COLD

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Extreme cold can pose significant risks to safety and health, especially when wind chill intensifies the freezing temperatures. Even moderate wind speeds can dramatically lower the "feels like" temperature, increasing the risk of frostbite.

When wind chill drops below -27°C, exposed skin can freeze in 30 minutes or less. At extreme levels, such as -40°C or colder, frostbite can occur in as little as 5-10 minutes.

To protect yourself and your loved ones, limit time spent outdoors during these dangerous conditions. If you must go outside, dress in multiple layers of loose-fitting, insulated clothing.

Make sure to cover all exposed skin with hats, scarves, gloves, and insulated boots. A windproof outer layer is essential to reduce the effects of cold winds.

Pay attention to frostbite warning signs, including numbness, tingling, or a loss of colour in fingers, toes, nose, or ears. If you suspect frostbite, immediately move to a warm location and avoid rubbing the affected area, as this can worsen tissue damage.

Hypothermia is another serious concern; symptoms include shivering, confusion, and slurred speech. Seek medical attention if hypothermia or frostbite is suspected.

For those driving during extreme cold, always keep an emergency kit in your vehicle with essentials such as blankets, extra clothing, food, and water.

Ensure your phone is fully charged, and let someone know your travel plans. Avoid leaving pets outdoors for extended periods, as they are equally susceptible to frostbite and hypothermia.

MONDAY

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The worst of the cold will likely occur Monday morning, especially in the west, with Arctic air entrenched across much of Central and Eastern Canada. Temperatures near or below -30°C will stretch from Alberta to Western Quebec.

Wind chills could make it feel like -40°C or colder across Saskatchewan, Manitoba, Northern Ontario, and parts of Eastern Alberta and Western Quebec. Calgary and Edmonton will escape the worst, but wind chills will still hover around -35°C.

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In Southern Ontario, most areas will see temperatures near -20°C, with Central and Southwestern Ontario experiencing the coldest air. Wind chills will make it feel like -25°C to -35°C, a pattern also expected in Montreal and Quebec City.

Atlantic Canada will begin to feel the polar plunge by Monday morning. Wind chills will drop to around -25°C in Northern New Brunswick, while Prince Edward Island and Nova Scotia will remain slightly milder, with wind chills ranging from -5°C to -15°C.

TUESDAY

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By Tuesday morning, the coldest air will shift further east, bringing some relief to the Prairies. Alberta will see temperatures climb back into the single digits, with wind chills in the teens.

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Eastern Saskatchewan will remain colder, with wind chills near -25°C to -30°C, while western regions warm slightly. Manitoba will also improve, though wind chills will still range from -30°C to -35°C, particularly near the Ontario border.

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Tuesday is likely to be the coldest day for Ontario, as the Arctic air peaks over the province. Northern Ontario will see temperatures between -30°C and -40°C, with wind chills plunging well into the -40s.

Southern Ontario will experience temperatures from -20°C to -30°C, with wind chills making it feel like -35°C to -40°C in Central Ontario and the Ottawa Valley, and -30°C to -35°C elsewhere.

Montreal and Quebec City will endure similarly bitter conditions, with wind chills of -35°C or lower. Central and Western Quebec will feel even colder, with wind chills dropping below -40°C.

Atlantic Canada will also face its coldest morning on Tuesday. Wind chills will range from -35°C in Northern New Brunswick to the -20s in Nova Scotia and Prince Edward Island.

WEDNESDAY

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Wednesday morning will bring one final bitterly cold start for much of Eastern Canada, but signs of improvement will begin to appear.

Southwestern Ontario, including Windsor, Sarnia, and London, could see wind chills near -35°C or even -40°C. Northern Ontario will finally climb above -30°C wind chills for the first time in days, marking the beginning of a warming trend.

Quebec will remain very cold, with wind chills near -40°C in some areas, while Montreal and Quebec City will continue to see wind chills of -35°C.

Atlantic Canada will face another cold morning, with wind chills between -20°C and -35°C.

Most of Eastern Canada will see a reprieve from the extreme cold by Thursday morning. However, this may only be temporary, as long-range models suggest another Arctic surge could arrive late next week into the weekend. Stay tuned for updates.

Widespread Temperatures Below -30°C and Windchills Approaching -45°C Have Prompted More Extreme Cold Warnings

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The extreme cold continues across Saskatchewan and Manitoba overnight tonight and through to tomorrow morning. Unfortunately, it will be colder than this morning, and a much larger area can expect temperatures below -30°C to settle in after midnight and continue until the late morning.

This intense cold poses a risk to everyone, especially young children, the elderly, individuals with chronic illnesses, outdoor workers, and those without adequate shelter. Symptoms of cold exposure, such as shortness of breath, chest pain, muscle pain and weakness, numbness, and colour change in fingers and toes, should be monitored closely.

The winds are expected be light again, at around 10-15km/h, as the temperatures reach their lowest point. With the even colder air than this morning, these light winds are going to result in windchills that are approaching -45°C. The coldest windchills are expected in the Westman Region, but windchills below -40°C will still be felt over a significant area. As a result, Environment Canada has issued more widespread Extreme Cold Warnings than last night, stretching from Saskatoon and into Northern Ontario.

At these temperatures, frostbite can occur in as little as 30 minutes, and in some areas close to 10 minutes, so it is crucial to cover up when going out and limiting exposure all together. It’s also wise to keep emergency supplies in your vehicle, including extra blankets and jumper cables, in case of an emergency.

Extreme Cold Makes Its First Appearance of December With Windchills Dipping Below -40°C

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The extreme cold has returned to the Prairies with temperatures dipping below -20°C across a majority of Saskatchewan and Manitoba, with the exception of the Southwest Corner of Saskatchewan. Temperatures will be lower than -30°C in parts of Central Saskatchewan and into the Parkland Region of Manitoba. The cold Arctic air pushed south throughout the day today and temperatures will continue to fall overnight before reaching their lowest point in the mid-morning.

This intense cold poses a risk to everyone, especially young children, the elderly, individuals with chronic illnesses, outdoor workers, and those without adequate shelter. Symptoms of cold exposure, such as shortness of breath, chest pain, muscle pain and weakness, numbness, and colour change in fingers and toes, should be monitored closely.

Winds overnight tonight are expected be light, at around 10-15km/h. These light winds will easily push the windchill below -40°C, which has prompted Environment Canada to issue Extreme Cold Warnings for parts of both provinces.

At these temperatures, frostbite can occur in as little as 30 minutes so it is crucial to cover up when going out and limiting exposure all together. It’s also wise to keep emergency supplies in your vehicle, including extra blankets and jumper cables, in case of an emergency.

Another Night of Extreme Cold on Tap, Warnings Extend into Manitoba for Tonight as Windchills Reach -40°C Over a Wider Area

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The extreme cold continues across the Prairies with overnight lows dipping below -20°C across a large part of the region and lower than -30°C in Central Saskatchewan once again tonight and into tomorrow morning.

This intense cold poses a risk to everyone, especially young children, the elderly, individuals with chronic illnesses, outdoor workers, and those without adequate shelter. Symptoms of cold exposure, such as shortness of breath, chest pain, muscle pain and weakness, numbness, and colour change in fingers and toes, should be monitored closely.

Winds overnight tonight are expected to remain similar to last night, peaking at around 10-15km/h, but they are expected to be more widespread. These light winds will easily push the windchill below -40°C over a larger area, resulting in Environment Canada issuing more Extreme Cold Warnings for tonight.

At these temperatures, frostbite can occur in as little as 30 minutes so it is crucial to cover up when going out and limiting exposure all together. It’s also wise to keep emergency supplies in your vehicle, including extra blankets and jumper cables, in case of an emergency.

It appears that Saskatchewan and Manitoba could see a bit of a reprieve tomorrow night, with the coldest air expected to be found in Alberta instead.

First Extreme Cold Air of the Season to Settle Across the Prairies Over the Coming Days, Overnight Lows Dipping Below -30°C

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While it has been quite cool across the Prairies this week on the backside of last weekend’s storm, it’s about to get even colder over the next few days. The first of this extreme cold will be experienced overnight Thursday and Friday morning. A large swath of the Prairies will have overnight lows below -20°C tonight while parts of Central Saskatchewan will see temperatures dipping below -30°C, prompting the first Extreme Cold Warnings of the season from Environment Canada that includes Saskatoon.

This intense cold poses a risk to everyone, especially young children, the elderly, individuals with chronic illnesses, outdoor workers, and those without adequate shelter. Symptoms of cold exposure, such as shortness of breath, chest pain, muscle pain and weakness, numbness, and colour change in fingers and toes, should be monitored closely.

Winds overnight are expected to top out at around 10-15km/h and while this is just a light breeze, it’ll be enough to drive the windchill well below -40°C in the coldest areas. At these temperatures, frostbite can occur in as little as 30 minutes so it is crucial to cover up when going out and limiting exposure all together. It’s also wise to keep emergency supplies in your vehicle, including extra blankets and jumper cables, in case of an emergency.

We will continue to provide updates over the coming days as these cold temperatures persist.