Clear and crisp this morning, but warming fast — a golden autumn day awaits

Thunder Bay is off to a cool and calm start this Sunday morning, with clear skies, light winds, and a brisk 5°C on the thermometer. But don’t let the chill fool you — a sunny and warm fall day is on the way, with highs near 24°C and a light southwest breeze. The next couple of days continue the pleasant autumn trend, with only minor cooling and increasing cloudiness expected by midweek.

Today’s Weather Overview

Current Conditions

As of 6:00 AM EDT at Thunder Bay Airport, the temperature is 4.5°C, with a dew point of 3.5°C, creating a humidity level of 93%—perfect for a crisp fall morning feel. Light winds from the west-southwest at 4 km/h contribute to calm, cool conditions.

Pressure is rising at 101.6 kPa, a sign of stable, fair weather under a high-pressure ridge.

Forecast for Sunday:

• Sunny skies all day.

• Winds becoming southwest 20 km/h late this morning.

• High of 24°C, feeling warm in the sun.

• UV index: 5 (moderate) — sun protection recommended if outdoors midday.

Tonight:

• Clear skies continue.

• Winds easing after sunset.

• Low of 9°C — mild and calm.

Extended Outlook

Monday, September 29:

• Sunny skies persist.

• High of 23°C — a beautiful fall day.

• UV index: 5 (moderate).

• Night: Clear, with a low of 11°C.

Tuesday, September 30:

• A mix of sun and cloud during the day.

• Slightly cooler with a high of 19°C.

• Night: Turning cloudy, with a low of 12°C.

Wednesday, October 1:

• Cloudy skies throughout the day.

• High of 19°C.

• Night: Remaining cloudy, with a low near 7°C.

Wardrobe Recommendations

With chilly mornings and sunny, warm afternoons, dress in layers to stay comfortable:

• Morning:

  • Warm coat or fleece and gloves if you’re heading out early.

• Afternoon (Sunday–Monday):

  • Switch to light long sleeves or t-shirts, as temperatures rise into the 20s.

• Evenings:

  • Sweater or light jacket will be needed after sunset as temperatures dip.

Weather Trivia

Did you know?
Thunder Bay often experiences its final 20°C+ day of the year in early October, making today and tomorrow potential contenders for the last summer-like warmth of 2025. Average highs for this time of year are closer to 15°C, so with a forecast high of 24°C, we’re enjoying a bonus stretch of fall heat — take advantage while it lasts!

Soak in the sunshine and warmth while it lasts! Stay tuned to the NetNewsLedger Weather Desk for continued updates as we wrap up September and welcome October.