Warm Weather, Hazy Conditions and a Chance of Overnight Showers
A Calm and Crisp Start to a Smoky Day
Thunder Bay, ON – Thursday, May 29, 2025: The city wakes up to mainly sunny skies and a crisp 7.7°C at 7:00 AM, as reported by Thunder Bay Airport. Humidity sits at 90%, making the morning feel fresh and just a little muggy. With a dew point of 6.1°C and winds from the west-southwest at 9 km/h, it’s a tranquil beginning to what will become a toasty and breezy day. Visibility is a clear 32 km, though wildfire smoke is expected to drift in late this morning and through the afternoon, putting a hazy filter on an otherwise summery day. The barometric pressure is at 101.7 kPa and falling, which hints at slight atmospheric instability — and possibly a few overnight surprises.
Summer-Like Heat Meets Hazy Afternoon Skies
Today’s forecast is all about heat and haze. Thunder Bay will see sunshine in the morning, turning to a mix of sun and cloud this afternoon, with local smoke making a return. Temperatures will climb to a warm 27°C, bringing the kind of weather that has you debating beach or backyard BBQ — just remember to keep the windows closed if the smoke rolls in heavily.
Winds will also pick up, shifting from a gentle morning breeze to westerlies gusting up to 40 km/h by early afternoon. If you’re biking, kayaking, or just trying to keep your hat on — prepare accordingly.
The UV index is 7, rated high, so don’t forget your sunscreen — even if the sunlight looks filtered through a smoky haze.
Smoky Night and Slight Shower Risk
Tonight, skies remain partly cloudy, with a 30% chance of showers overnight. Local smoke will linger, so it’s wise to keep those bedroom windows closed if you’re sensitive to poor air quality. The overnight low of 14°C will keep things warm, but with the added humidity and smoke, it may not feel all that refreshing.
Friday Brings More Smoke, Less Heat
Friday will be sunny with lingering smoke in the morning, and a slightly cooler high of 23°C. Winds shift north and gust up to 40 km/h, which could clear the air or send new smoke your way — it’s a bit of a wild card. The evening clears right up with a crisp low of 5°C, giving some welcome relief.
Weekend Outlook: Clear, Calm and Classic
The weekend looks practically perfect. Saturday will be sunny with a high of 21°C, and Sunday warms up again to 23°C, both days with clear skies at night and cool lows around 5–8°C — ideal for bonfires, stargazing, and maybe even a dip in the lake if you’re brave enough.
What to Wear?
Summer gear is officially in play: T-shirts, sunglasses, sandals — check. But don’t let the haze fool you — UV rays are still strong. Keep sunscreen handy, and consider wearing a NIOSH-certified mask if you’re spending time outside during smoky periods. If you’re doing yard work, limit strenuous activity when the smoke peaks.
Historical Highs and Lows for May 29
Thunder Bay’s weather history shows a record high of 31.2°C and a record low of -2.5°C for May 29. While today’s high of 27°C won’t break any records, it’s still a solid warm-up to summer — especially when paired with that northern Ontario sunshine.
Thunder Bay Trivia: Why So Smoky?
Thunder Bay often sits at the convergence of air masses that funnel wildfire smoke from both the prairies and northern forests. Combined with light winds and warmer temperatures, this makes the region a prime recipient of atmospheric “smoke mail.” Stay alert to air quality advisories — and maybe hold off on the backyard campfire.
