Thunder Bay’s Oct. 4–6 forecast: gusty Sunday, sunny Monday and strong winds on western Lake Superior
THUNDER BAY — WEATHER — Sunday, Oct. 4, 2026: Thunder Bay faces a windy Sunday before sunshine returns Monday and temperatures climb Tuesday. On western Lake Superior, a strong wind warning is in effect, with northwest winds forecast at 25 knots today and tonight.
Thunder Bay: Three-Day Forecast for Oct. 4–6
Sunday, Oct. 4: Clouds and Gusty Northwest Winds
Expect mainly cloudy skies with a 30 per cent chance of morning showers. Northwest winds will increase to 30 km/h, gusting to 50, with an afternoon high of 15°C. The UV index is 3, or moderate.
Tonight, skies become clear after midnight. Winds ease near midnight, and the temperature falls to 0°C. Gardeners should consider protecting frost-sensitive plants.
Monday, Oct. 5: Sunshine and a Cool Start
Monday brings sunny skies and a high of 13°C. A warm layer will be useful for the early school run or commute.
Cloudy periods develop Monday night, with a low of 4°C.
Tuesday, Oct. 6: Warmer Autumn Weather
Tuesday looks sunny, with the high reaching 19°C.
Cloudy periods return overnight, along with a 30 per cent chance of showers and a low of 6°C.
Lake Superior West: Strong Wind Warning
Environment and Climate Change Canada’s marine forecast, issued at 3 a.m. EDT Sunday, calls for the following conditions over western Lake Superior:
| Day | Marine wind forecast |
|---|---|
| Sunday, Oct. 4 | Northwest 25 knots, continuing tonight. Periods of rain end this morning. |
| Monday, Oct. 5 | Northwest 15 knots in the morning, easing to west 10 knots in the afternoon, then increasing to southwest 15 knots in the evening. |
| Tuesday, Oct. 6 | The extended Lake Superior outlook calls for south 15 knots, increasing to southwest 25 knots in the afternoon. |
Sunday’s 25-knot winds are approximately 46 km/h. The marine forecast describes offshore conditions; winds near shore can differ considerably because of the coastline.
A current wave-height forecast for Oct. 4–6 could not be verified, so specific wave heights are not included. Boaters should check the latest Environment Canada marine forecast and Canadian Coast Guard weather broadcasts before departure.
Planning Your Next Three Days
A wind-resistant jacket will be useful Sunday, especially along exposed stretches of the waterfront. Prepare for a cold start Monday, then lighter layers Tuesday afternoon.
For boaters, warmer air on Tuesday does not mean calmer water: the extended forecast calls for winds to strengthen again that afternoon.
Forecast basis: Thunder Bay public forecast issued at 7:13 p.m. EDT Oct. 3, and marine forecasts issued at 3 a.m. EDT Oct. 4. Conditions and warnings may change.
