Thunder Bay Three-Day Forecast: Showers Tonight and Wind Gusts to 70 km/h Tuesday

THUNDER BAY — WEATHER — Monday, September 14, 2026 — Thunder Bay’s next three days bring sunshine, overnight showers and a windy Tuesday before sunny skies return Wednesday.

This September 14–16 outlook is based on Environment Canada’s forecasts issued at 5:30 a.m. EDT September 14.

Monday, September 14: Sunshine Before Overnight Showers

Monday starts sunny, with a mix of sun and cloud developing this afternoon. South winds will increase to 20 km/h, gusting to 40 km/h. The high is 18°C, with a moderate UV index of 5.

Showers tonight will bring 10–15 mm of rain before ending ahead of morning. A 40 per cent shower chance remains afterward. Southeast winds gusting to 40 km/h turn southwest after midnight. The low is 11°C.

Tuesday, September 15: Strong West Winds

Expect mainly cloudy skies and a 40 per cent chance of showers. Southwest winds gusting to 50 km/h will become west at 40 km/h, gusting to 70 km/h late in the morning.

The high is 18°C, with a moderate UV index of 3.

Wednesday, September 16: Sunshine Returns

Tuesday night will be clear with a low of 7°C. Wednesday brings sunshine and a high of 19°C.

Clouds return Wednesday night with a 40 per cent chance of showers and a low of 10°C.

What This Means for Your Plans

Tuesday’s forecast gusts deserve attention. Secure bins, patio furniture and other loose items beforehand. Drivers of trucks, recreational vehicles and vehicles towing trailers should be prepared for crosswinds in exposed areas.

Keep a rain jacket handy for Monday evening and Tuesday. Wednesday offers a better outlook for outdoor activities.

This report does not confirm highway closures. Check Ontario 511 for road conditions and review updated forecasts and alerts at Environment and Climate Change Canada before travelling.