Foggy Beginnings, Flurry Endings – Weather in Thunder Bay for October 29, 2025
THUNDER BAY – If you woke up and thought someone replaced your windows with frosted glass, you’re not alone. Thunder Bay is currently seeing areas of fog, with visibility reduced to just 0.6 km at the Thunder Bay Airport.
The morning temperature is holding steady at 4.0°C, and with a dew point matching exactly at 4.0°C, it’s no surprise the humidity is at a full 100%.
Translation: the air is practically holding its breath.
Winds are light from the west-northwest at 4 km/h, barely enough to rustle a leaf. Meanwhile, the barometric pressure is 102.8 kPa and rising, a subtle nudge from the atmosphere that calmer, clearer conditions are on the horizon—eventually.
Expect the fog patches to clear out late this morning, revealing a more cheerful mix of sun and cloud. The high today is a relatively warm 11°C, and with a low UV index of 2, you won’t need to hunt down your sunglasses unless you’re just committed to the aesthetic.
Tonight and Thursday – Fog Returns Before a Halloween Chill
Tonight, skies remain partly cloudy, but just when you thought the fog was gone—it sneaks back in near midnight. The overnight low will dip to +2°C, making for a damp and misty sleep.
Thursday, October 30, starts off mainly cloudy, with fog patches once again making an early appearance. They’ll clear by mid-morning, and the temperature will climb to a comfortable 10°C. But hold onto your cozy socks—Thursday night brings cloudy skies with a 30% chance of rain showers or flurries, and the low slips to +1°C. It’s beginning to look a lot like “wait, was that snow?”
Friday into the Weekend – A Frosty Halloween Forecast
Friday, October 31, delivers that quintessential cloudy, chilly Halloween vibe, with another 30% chance of rain or flurries and a daytime high of just 6°C. Trick-or-treaters may want to add a base layer under those costumes—or risk becoming a popsicle dressed as Batman.
Friday night sees the cold deepening to -3°C, and yes, flurries may make a guest appearance once again. Bundle up, and be cautious—those porch steps may get a little slick.
Historic Highs and Lows
On this day in Thunder Bay’s weather history, the record high soared to 20.6°C, while the record low took a sharp dive to -13.9°C. That’s a 34-degree swing, which in true Northern Ontario style, reminds us: always expect the unexpected.
What to Wear?
Today’s foggy dampness calls for something warm yet breathable. Think fleece-lined layers, a water-resistant jacket, and waterproof footwear. Visibility will improve later, but if you’re driving this morning, fog lights are a must. As we head into the weekend, don’t pack away the gloves and hats just yet—flurries may be light, but they still bite.
Weather Trivia – Did You Know?
Thunder Bay is one of Canada’s sunniest cities, clocking in over 2,200 hours of sunshine per year. But you’d never guess it on mornings like this when the fog rolls in thick enough to hide the Sleeping Giant.
