Fog advisory in effect Friday morning, followed by a hot and humid weekend — cooler air arrives by Monday

THUNDER BAY – WEATHER – Thunder Bay is waking up under a Fog Advisory this Friday morning, with near-zero visibility at times and 100% humidity.

As the fog burns off, the region will see sunshine and unseasonably warm temperatures through the weekend, with humidex values reaching 32°C Saturday — more typical of July than October.

However, a cool front arrives by Sunday night, ushering in gusty winds, drizzle, and a return to fall-like weather on Monday.

Fog Advisory Details – Friday, October 3

• Advisory for: City of Thunder Bay

• Issued due to: Locally dense fog with visibility reduced to 0.4 km or less.

• Hazard: Sudden drops in visibility on roads, especially in low-lying areas or near water.

• Travel Advisory: If driving, turn on headlights, slow down, and maintain safe distances. Fog will dissipate mid-morning.

Current Conditions (as of 6:00 AM EDT)

• Location: Thunder Bay Airport

• Temperature: 12.1°C

• Dew Point: 12.1°C

• Humidity: 100%

• Wind: WSW at 8 km/h

• Visibility: 0.4 km (dense fog)

• Pressure: 101.8 kPa (falling)

• Condition: Fog

Weekend Forecast

Friday, October 3:

• Morning: Fog dissipating by mid-morning.

• Afternoon: Sunny and warm.

• High: 24°C, Humidex: 27

• UV Index: 4 (moderate)

Tonight:

• Increasing cloudiness, with a 40% chance of drizzle overnight.

• Fog patches developing after midnight.

• Low: 11°C, but rising to 14°C by morning.

Saturday, October 4:

• Morning: Cloudy with a 40% chance of drizzle, and fog patches early.

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

• Wind: Becoming south at 20 km/h, gusting to 40 km/h.

• High: 27°C, Humidex: 32 — extremely warm for October.

• UV Index: 4 (moderate)

Saturday Night:

• Cloudy periods.

• Low: 17°C

Sunday, October 5:

• Day: Cloudy and windy as the cold front approaches.

• High: 25°C

• Evening/Night: Cloudy with a 30% chance of showers and strong winds.

• Low: 7°C

Monday, October 6:

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

• Cooler with a high of 14°C

• Night: Cloudy periods, with a low of +4°C

Aviation Weather (IFR/VFR Conditions)

• Friday morning: IFR conditions across the region due to fog, with ceilings and visibility below VFR minimums.

• Improving to VFR by mid-morning, with good visibility and clear skies Friday afternoon.

• Saturday morning: Possible marginal VFR/IFR with fog and drizzle — pilots should monitor TAF/METAR updates.

• Winds gusty Saturday–Sunday, creating moderate turbulence and potential for crosswind issues on smaller runways.

• Monday: VFR returns, but expect scattered cloud decks and possible brief precipitation.

Wardrobe Recommendations

• Friday:

  • Start with light layers for the cool, damp morning.

  • Short sleeves by midday with warm sun.

• Saturday:

  • Hot and humid — wear summer attire and stay hydrated.

  • Windbreaker useful due to gusty winds.

• Sunday:

  • Still warm, but windy — secure loose items outdoors and wear layers.

• Monday:

  • Back to fall clothing — long sleeves, jackets, and closed shoes.

Weather Trivia

Did you know?
Thunder Bay’s normal high for early October is around 13°C, making Saturday’s forecast high of 27°C with a humidex of 32°C more typical of mid-summer than fall. This kind of extreme warmth in October is rare and usually signals a significant cold front on the way — which we’ll see Sunday night into Monday.

Use caution in Friday’s fog, then enjoy the rare warmth — and stay weather-ready as cooler air returns next week.For continuing updates, trust the NetNewsLedger Weather Desk.