Thunder Bay Set for a Spring Snow Slam as Welcome Islands Heat Up (Relatively Speaking)

Thunder Bay braces for a spring storm bringing 10 to 20 cm of snow, ice pellets, and freezing rain Friday. Expect tough travel and cold nights into the weekend

THUNDER BAY, ON – March 27, 2025 – While most of Northwestern Ontario is bundling up under wintry skies, the Welcome Islands are ironically Ontario’s hot spot this morning at a balmy +3°C.

But don’t let that springlike warmth fool you — a Special Weather Statement is in effect for Thunder Bay, warning of a significant spring snowstorm on the way. The low-pressure system is expected to sweep through the region starting late Thursday evening, dumping 10 to 20 cm of snow, with blowing winds, freezing rain, and ice pellets possible, especially near the international border.

Sounds like a weekend of snow shovels and slipperiness awaits.

Current Conditions – Cool, Calm, and Quiet… For Now

At 6:00 AM EDT, the weather in Thunder Bay is partly cloudy with a temperature of +1.1°C. The wind from the northwest at 10 km/h is making it feel cooler, and the wind chill was down to -8°C earlier this morning. Humidity is at 74%, and the barometric pressure sits at 101.6 kPa and rising, signalling temporary stability before the system moves in.

Today brings a mix of sun and cloud, with a 40% chance of flurries this morning. Winds will shift, becoming light near noon, and the high temperature will reach +2°C, a decent day for late March — but it’s just the calm before the snowstorm.

Snow Moves in Tonight, Intensifies Through Friday

Thursday night, skies will cloud over by late evening as the snow begins, with 2 to 4 cm expected overnight. Winds will be light at first, up to 15 km/h, and temperatures will fall to a low of -4°C, with a wind chill near -9°C.

Friday is the real snow day. Expect heavy snow or ice pellets, especially in the afternoon, with local blowing snow reducing visibility. 10 to 15 cm of accumulation is likely, with winds picking up from the east at 30 km/h, gusting to 50. The high will struggle to reach -1°C, with a wind chill near -10°C. Perfect conditions for snow to stick to everything — roads, trees, power lines, you name it.

The snow continues Friday night, with lows near -7°C, and travel conditions could be challenging to downright dangerous, especially during the heaviest bursts of snowfall.

Weekend Outlook – Some Sunshine, Some Flurries, and Some Serious Cold at Night

Saturday looks to bring some relief, though still with a 60% chance of snow, and a high near +1°C. The skies will begin to clear by evening, but the clear skies come at a price: an overnight low of -9°C.

Sunday turns the dial toward more classic spring: sunny skies, a high of zero, and a crisp, clear night with the mercury plunging to -14°C. Monday stays sunny and bright with a high of zero, and another cold night around -12°C.

Bundle Up and Stay Ready — Snow Blowers Might Be the Real MVPs

While the Welcome Islands bask in their fleeting springlike glory, Thunder Bay is in full-on snow alert mode. The combination of accumulating snow, gusty winds, and the risk of ice pellets or freezing rain Friday makes for a messy setup. If you’re planning to be on the roads, expect reduced visibility and slow travel. If you’re planning to stay in — excellent choice.

Dress in full winter regalia: insulated layers, waterproof boots, windproof jackets, and gloves that can still grip a snow shovel. And keep a flashlight handy — wet snow and wind can lead to power outages, especially if ice builds up on lines.

Thunder Bay’s Snowy Spring Past

On this date, Thunder Bay has seen it all. The record high for March 27 is 13.9°C (1999), while the record low sinks to -27.8°C (1972). Today’s mix of light snow, ice pellets, and moderate temps falls squarely in that unpredictable late-March zone.

Did you know? The Welcome Islands, located just off Thunder Bay in Lake Superior, are often among Ontario’s warmest or coldest spots in spring, thanks to the microclimate effects of the lake. Today, they’re the hot spot in Ontario at +3°C — a rare title, and one that won’t last long.