Chilly start this morning, but a warm and sunny weekend is on the horizon!

THUNDER BAY – WEATHER – Thunder Bay is waking up to another crisp September morning, with temperatures just above freezing and clear skies overhead. Showers and a possible thunderstorm may make a brief appearance this morning, but those will quickly clear out, making way for breezy, sunny conditions by the afternoon.

If you’re making weekend plans, you’re in luck—Sunday and Monday look absolutely stunning, with sunshine and highs in the 23–24°C range.

Current Conditions – Saturday, September 27

• Observed at: Thunder Bay Airport

• Time: 3:00 AM EDT

• Temperature: 4.3°C

• Dew Point: 3.4°C

• Humidity: 94%

• Wind: WNW at 4 km/h

• Visibility: 24 km

• Pressure: 100.9 kPa (falling)

• Sky: Clear

Expect fog or frost in localized areas this morning due to light winds and radiational cooling.

Weekend Forecast

Saturday, September 27:

• Morning:

  • Mainly cloudy with a 40% chance of showers and risk of a thunderstorm.

  • Showers will clear by noon, and skies will brighten.

  • Winds becoming west at 30 km/h, gusting to 50 km/h—hold onto your hats!

• Afternoon:

  • Clearing skies with a warm high of 21°C.

  • UV index 4 (moderate) — bring sunglasses and apply sunscreen if you’ll be outside.

• Tonight:

  • Clear skies.

  • Winds west at 20 km/h, gusting to 40, becoming light this evening.

  • Low of 8°C — perfect for a fall evening walk or bonfire.

Thunder Bay Images

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Sunday, September 28:

• All day:

  • Sunny and warm—a picture-perfect fall day.

  • High of 24°C — nearly 10°C above seasonal averages!

  • Light winds and dry conditions make it ideal for hiking, biking, or lake activities.

• Night:

  • Clear skies.

  • Low of 7°C — cool and calm.

Monday, September 29:

• Daytime:

  • Another sunny day, with a high of 23°C.

  • Light winds and dry air make it a great day for commuting or outdoor meetings.

• Night:

  • A few cloudy periods roll in.

  • Low of 10°C — still mild for this time of year.

Wardrobe Recommendations

• Saturday Morning:

  • Bundle up with gloves, scarf, and a fall jacket for the early chill.

  • Pack rain gear or an umbrella in case the showers roll through before noon.

• Saturday Afternoon to Monday:

  • Layers work best—long sleeves or flannel in the morning, transitioning to light shirts or sweaters by mid-day.

  • Windbreaker for Saturday’s gusty conditions.

  • Evenings will be cool, so don’t forget a jacket or hoodie.

Weather Trivia

Did you know?
September 27 marks one of the latest “summer-like” days in recent Thunder Bay weather history. With a forecast high of 24°C on Sunday, this weekend could go down as one of the warmest final weekends of September in over a decade. Typically, highs by now hover around 15°C, making this weekend’s weather 10°C warmer than average.

Enjoy this gorgeous fall weekend in Thunder Bay—and don’t forget your shades! Stay tuned to the NetNewsLedger Weather Desk for your next update.