Misty start Saturday gives way to record-challenging warmth — then cooler air returns Monday.

THUNDER BAY – WEATHER – It’s a damp and misty morning in Thunder Bay, with 100% humidity and low visibility, but don’t let the grey skies fool you — the weekend is set to deliver exceptionally warm, summer-like conditions, with humidex values reaching into the low 30s today. Winds will pick up later, and a few showers are possible overnight and into Sunday, but overall, it’s shaping up to be a spectacular early October weekend before cooler air settles in Monday.

Current Conditions (as of 6:00 AM EDT – Thunder Bay Airport)

• Temperature: 14.1°C

• Dew Point: 14.1°C

• Humidity: 100%

• Wind: East at 9 km/h

• Visibility: 5 km (reduced due to mist)

• Pressure: 101.3 kPa (falling)

• Condition: Mist

Saturday, October 4

• Morning: Cloudy with fog patches and mist; visibility improving mid-morning.

• Late Morning to Afternoon: Clearing skies, becoming sunny and hot.

• Wind: South 20 km/h gusting to 40 km/h.

• High: 27°C, Humidex: 33 — record-challenging warmth

• UV Index: 4 (moderate)

Tonight:

• Partly cloudy.

• 30% chance of showers overnight.

• Wind: South 20 km/h gusting to 40 km/h

• Low: 18°C

Sunday, October 5

• A mix of sun and cloud.

• 30% chance of showers early morning and again late in the afternoon.

• Wind: Becoming southwest 30 km/h, gusting to 60 km/h near noon.

• High: 25°C, Humidex: 28

• UV Index: 4 (moderate)

Sunday Night:

• Cloudy periods, with a 30% chance of showers.

• Low: 9°C

Monday, October 6

• A mix of sun and cloud, with a 30% chance of showers.

• Much cooler with a high of 17°C.

Monday Night:

• Clear skies

• Low: +4°C

🌬️ Advisory Notes & Activity Planner

🧭 Wind Advisory:

• Gusty southerly winds (up to 60 km/h) Sunday may impact lake activities, outdoor events, and high-profile vehicles.

🌿 Gardeners Take Note:

• No frost expected, but warm humid air followed by rapid cooling Monday could stress late-season plants.

👟 Outdoor Recreation:

• Ideal Saturday afternoon for parks, patios, and hiking.

• Winds increase Sunday — use caution on bikes and boats.

👚 Wardrobe Recommendations

• Saturday & Sunday Daytime:

  • Shorts, t-shirts, breathable layers.

  • Hat, sunglasses, and sunscreen still important.

• Evenings:

  • Light jacket or hoodie.

  • Sunday night will feel much cooler than Saturday.

• Monday:

  • Return to fall attire — long sleeves, jacket, and closed footwear.

Weather Trivia

Did you know?
Thunder Bay’s record high for October 4 is 26.5°C, and today’s forecast of 27°C with a humidex of 33°C may break that record. October heat waves this strong are rare but not unheard of — they typically signal a powerful frontal boundary on the way, which we’ll see arrive Sunday night with a sharp temperature drop of nearly 10°C by Monday.

Enjoy the summer-like heat while it lasts, and stay weather-aware for gusty winds and changing conditions Sunday into Monday.
— NetNewsLedger Weather Desk