Thunder Bay – WEATHER – Thunder Bay wakes up under a veil of mist this morning, with high humidity and overcast skies setting the stage for a cooler, damp day ahead. While the drizzle threat lingers, summer warmth will quickly return midweek, with humidex values pushing conditions into the low 30s by Wednesday.
Today’s Weather Overview
Current Conditions
At 7:00 AM EDT at Thunder Bay Airport, the temperature is 15.6°C, with the dew point matching, leading to 100% humidity and misty conditions. Winds are very light from the northeast at 4 km/h, barometric pressure is at 101.7 kPa and falling, and visibility sits at 10 km despite pockets of mist near Lake Superior.
Today will stay cloudy with a 40% chance of showers or drizzle, especially through the morning and early afternoon. Fog patches will lift as the day progresses. Temperatures will rise to a high of 21°C, but it will feel more like 26°C with the humidex. The UV index is 5, or moderate.
Tonight remains cloudy with a 40% chance of evening showers. Fog patches are likely to redevelop near midnight, with a low of 14°C.
Extended Weather Forecast
Expected Conditions
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Wednesday, August 20: Cloudy skies will dominate, though fog patches will burn off in the morning. It will be warmer and muggy, with a high of 25°C, feeling closer to 32°C with the humidex. The UV index stays moderate at 5.
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Wednesday Night: Cloudy periods with a mild overnight low of 12°C.
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Thursday, August 21: A mix of sun and cloud with warm, pleasant conditions. Temperatures climb to a high of 25°C.
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Thursday Night: Clouds increase with a 60% chance of showers and a mild low of 16°C.
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Friday, August 22: Mostly cloudy with a 40% chance of showers. Temperatures hold steady at 25°C, continuing the late-summer warmth.
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Friday Night: Cloudy periods with a 40% chance of showers and a low near 13°C.
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Wardrobe Recommendations
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Today: A light jacket or sweater is recommended for the cooler, damp conditions this morning, along with waterproof footwear in case of drizzle.
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Wednesday: Summer wear will be needed — breathable clothing, hats, and sunscreen for the humid heat.
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Thursday & Friday: Comfortable summer attire works well, but carry a rain jacket or umbrella as showers become more likely in the evenings.
Weather Trivia
Did you know? Thunder Bay is known as one of the sunniest cities in Eastern Canada, averaging over 2,100 hours of sunshine per year. While today begins cloudy and misty, the city typically enjoys bright skies, especially in late summer when Lake Superior breezes help clear the air.
