Cold Mornings, Mild Afternoons, and a Stormy Mix for Some Regions

Ontario sees spring warmth in the south, winter storms in the north, and freezing rain in central regions. Get the latest 3-day forecast across the province

As March 19, 2025, unfolds across Ontario, residents are experiencing a diverse range of weather conditions, from mild spring-like warmth in the south to biting cold and flurries in the north. While southern Ontario enjoys a brief taste of spring with sunshine and highs nearing 18°C in Toronto, the north remains firmly in winter’s grip, with wind chills plunging as low as -25°C in some communities. Meanwhile, Sault Ste. Marie and Sudbury are bracing for a messy mix of rain, freezing rain, and snow as a strong low-pressure system moves in.

Ontario Weather Highlights: March 19-21, 2025

• Southern Ontario (Toronto, GTA, Windsor, London, Niagara): Mild and sunny today, with temperatures soaring to 18°C in Toronto before clouds and showers arrive overnight. A cooldown begins Thursday, with rain turning to flurries by Friday.
• Central Ontario (Sudbury, North Bay, Algonquin Region): Rain today, with freezing rain and snow arriving overnight into Thursday. Conditions will turn slick and hazardous, with ice buildup possible before a return to colder temperatures by Friday.
• Northeastern Ontario (Sault Ste. Marie, Timmins, Cochrane, Wawa): A winter storm warning remains in effect for areas along the rain-snow transition line, bringing a messy mix of rain, freezing rain, and up to 20 cm of snow by Thursday morning.
• Northwestern Ontario (Thunder Bay, Kenora, Dryden, Sioux Lookout, Vermilion Bay): Chilly mornings and sunny afternoons today, but flurries return Thursday night. Expect highs between -2°C and +3°C, but overnight lows will remain frigid, dipping to -19°C or colder by Friday night.
• Far-Northern Ontario (Sachigo Lake, Fort Severn, Attawapiskat, Bearskin Lake): Bitterly cold mornings, with wind chills near -20°C to -25°C. Some sunshine today, but clouds and flurries will move in by Thursday night. Highs remain between -2°C and -10°C, with nighttime lows as cold as -26°C.

Southern Ontario: Warm Today, Showers and a Cooldown Coming

Toronto & GTA

• Wednesday: Sunny and warm, high 18°C, breezy south winds.
• Tonight: Clouds increase, 60% chance of showers, low 10°C.
• Thursday: Cloudy with rain showers, turning colder in the evening, high 13°C.
• Friday: Chance of flurries, high 1°C, much cooler.

Windsor & London

• Today: Warm with highs near 16°C before showers develop overnight.
• Thursday: Cloudy with rain, high 11°C.
• Friday: Turning colder with a mix of flurries and rain showers, high 2°C.

Central Ontario: Rain, Freezing Rain, and Snow Incoming

Sudbury & North Bay

• Today: Cloudy with rain arriving in the afternoon, high 5°C.
• Tonight: Steady rain (10-15 mm), risk of freezing rain, low 0°C.
• Thursday: Freezing rain and rain turning to snow, 5 cm expected, high 0°C before falling to -4°C.
• Friday: Increasing cloudiness, chance of flurries, high +3°C.

Northeastern Ontario: Winter Storm Warning in Effect

Sault Ste. Marie & Wawa

• Today: Rain mixed with freezing rain, high 4°C.
• Tonight: Freezing rain changing to snow (5-10 cm expected), gusty winds, low -3°C.
• Thursday: Snow continues before clearing, high 0°C.
• Friday: Cloudy with flurries, high 1°C.

Northwestern Ontario: Sunshine Before Flurries Return

Thunder Bay

• Today: Sunny, becoming partly cloudy, high 7°C.
• Tonight: Clear and cold, low -10°C.
• Thursday: Mainly sunny, high 5°C.
• Friday: Flurries possible, turning much colder, high -1°C, low -19°C.

Kenora, Dryden & Sioux Lookout

• Today: Sunny with a high of -1°C, light northwest winds.
• Tonight: Increasing cloudiness, low -14°C.
• Thursday: Cloudy with flurries late, high +3°C.
• Friday: Flurries continue, temperatures dropping, high -6°C, low -23°C.

Far-Northern Ontario: Frigid Mornings, Scattered Flurries

Sachigo Lake, Fort Severn, Sandy Lake, Bearskin Lake, Attawapiskat

• Today: Sunny with a few clouds, highs between -5°C and -10°C.
• Tonight: Clear and bitterly cold, lows near -18°C to -25°C.
• Thursday: Increasing clouds, flurries possible, highs -4°C to -7°C.
• Friday: Cold with scattered flurries, highs -6°C to -12°C, lows -20°C to -26°C.

What to Expect Next?

• Southern Ontario: Today’s warmth won’t last—expect showers, a temperature drop, and even flurries by Friday.
• Central & Northeastern Ontario: A wintry mix of rain, freezing rain, and snow through Thursday before cooling down.
• Northwestern & Far-Northern Ontario: Cold nights continue, with scattered flurries by Friday.

What to Wear?

• Southern Ontario: Light layers today, but keep a rain jacket handy for tonight’s showers.
• Central & Northeastern Ontario: Waterproof gear for rain today, icy conditions possible Thursday.
• Northern Ontario: Full winter gear still needed! Wind chills will make mornings feel bitterly cold.

Weather Trivia

Did you know that Toronto once hit 24.4°C on March 19, 2012, while Sudbury saw -30.6°C on the same date in 1965? That’s nearly a 55-degree difference in recorded history!

Spring is just around the corner, but as this week shows, winter isn’t quite ready to leave Ontario yet!