Thunder Bay will see morning drizzle and fog Wednesday, west winds gusting to 50 km/h Thursday, and sunny but cooler conditions Friday
THUNDER BAY – WEATHER DESK – September 30, 2026 – Thunder Bay will see a warm start to the three-day forecast, followed by stronger west winds and a cooler finish. Wednesday will bring morning drizzle and fog patches before clearing. Thursday will be sunny but windy, while Friday is expected to be sunny and cooler.
Environment and Climate Change Canada is forecasting no snow or freezing rain during this period. The main concerns are reduced visibility early Wednesday, crosswinds Thursday and a sharp drop in overnight temperatures by Friday morning.
Three-Day Forecast
| Day | Forecast | High | Night |
|---|---|---|---|
| Wednesday, Sept. 30 | Mainly cloudy with a 40 per cent chance of drizzle in the morning. Fog patches will dissipate, followed by clearing in the afternoon. West wind 20 km/h, gusting to 40 late in the morning. Humidex 29. | 24 C | Clear at first, then increasing cloud and a 30 per cent chance of showers before morning. Low 11 C. |
| Thursday, Oct. 1 | Sunny, with a west wind of 30 km/h gusting to 50 in the morning. The wind may make the day feel cooler, especially near the waterfront and on exposed roads. | 18 C | Clear. Low 5 C. |
| Friday, Oct. 2 | Sunny and cooler. Current ECCC guidance does not indicate significant precipitation. | 15 C | Clear. Low 3 C. |
Wednesday: Warm, Damp Early and Clearing Later
Thunder Bay Airport was reporting cloudy conditions and 16 C during the overnight observation. Wednesday morning may begin with drizzle and fog patches. Visibility should improve as the fog dissipates.
The afternoon will be much warmer, with a forecast high of 24 C and a Humidex near 29. The west wind will increase to 20 km/h, with gusts to 40. The wind may move unsecured outdoor items and create crosswinds for trucks, trailers and campers.
Thursday: Sunny but Windy
Thursday will be sunny with a high near 18 C. The strongest winds of the forecast period are expected in the morning, when west winds may reach 30 km/h with gusts to 50.
Drivers should use extra care on exposed sections of Highway 11/17, Highway 61 and rural roads around Thunder Bay. Motorists operating high-profile vehicles should reduce speed if the vehicle begins to sway or the steering becomes difficult.
Friday: Cooler Sunshine
Friday is expected to be sunny with a high near 15 C. The overnight low may fall to 3 C, which could produce frost in sheltered rural areas outside the city. People with gardens, plants or outdoor plumbing should prepare for a chilly start.
Travel and Outdoor Safety
- Use low-beam headlights in Wednesday morning fog and drizzle.
- Leave extra following distance on wet roads and watch for leaves covering pavement.
- Secure patio furniture, signs, tarps and construction materials before Thursday winds strengthen.
- Check road conditions before travelling outside the city, particularly on exposed stretches of Highway 11/17.
- Dress in layers for outdoor work. The afternoon may be mild, but Thursday night and Friday morning will be much cooler.
Lake Superior and Harbour Conditions
West winds gusting to 50 km/h can make exposed areas of Lake Superior choppy, even when the harbour appears relatively calm. Small-boat operators should check the latest marine bulletin before leaving shore, wear an approved personal flotation device and avoid relying on sheltered harbour conditions as a guide to open-lake conditions.
Cold water remains a serious risk. Boaters should carry reliable communications, tell someone their route and return before winds become uncomfortable.
Weather Alerts and Air Quality
No Thunder Bay weather warning, watch or advisory was identified in the ECCC information reviewed for this report. No air-quality concern was identified in the material checked. Alerts and air-quality information can change quickly, so residents should check the official ECCC pages immediately before travel or outdoor work.
Overview
Thunder Bay will see morning drizzle and fog Wednesday, west winds gusting to 50 km/h Thursday, and sunny but cooler conditions Friday.
