Thunder Bay weather for June 4, 2026: A Yellow Severe Thunderstorm Watch is in effect with light rain, 11.7°C, 60 percent chance of showers, thunderstorm risk, wind gusts up to 90 km/h, and toonie-sized hail possible.
Thunder Bay is under a Yellow Watch – Severe Thunderstorm this afternoon as unsettled weather moves across the city. Environment Canada says conditions are favourable for severe thunderstorms capable of producing wind gusts up to 90 km/h and toonie-sized hail this afternoon and evening. Local utility outages are possible if storms strengthen.
Today’s Weather Overview
Current Conditions
At 2:00 PM EDT Thursday, June 4, 2026, conditions at Thunder Bay Airport were reported as a light rainshowerwith the temperature at 11.7°C. The air is damp, with a dew point of 10.1°C and humidity at 90 percent. Winds are from the northeast at 10 km/h, visibility is 16 km, and the barometric pressure is 101.5 kPa and rising.
For the rest of today, Thunder Bay can expect mainly cloudy skies with a 60 percent chance of showers and a risk of thunderstorms. The high is forecast to reach 19°C, with a UV index of 6, or high.
Severe Thunderstorm Watch
A severe thunderstorm watch means storms have not necessarily become severe yet, but the atmosphere is favourable for them to develop. Environment Canada says the main threats for Thunder Bay are strong wind gusts, large hail, and storms developing through the afternoon into the evening.
Residents should move indoors if threatening weather approaches. The safest place is a basement or an interior room away from windows. If you are outside, protect yourself from flying debris and hail. Remember: when thunder roars, go indoors.
Tomorrow’s Forecast
Expected Conditions
Tonight: Thunder Bay will see partly cloudy skies with a 60 percent chance of showers and a continued risk of thunderstorms. The overnight low will be 11°C.
Friday, June 5: Conditions improve slightly, with a mix of sun and cloud and a 40 percent chance of showers. There is still a risk of a thunderstorm in the afternoon. The high will reach 23°C, with a humidex of 25 and a UV index of 7, or high. Friday night brings cloudy periods with a 30 percent chance of showers and a low of 8°C.
Saturday, June 6: A brighter weekend begins with sunny skies and a high of 25°C. Saturday night will be clear, with a low of 9°C.
Sunday, June 7: Sunshine continues with a high of 24°C and a clear night near 10°C.
Wardrobe Recommendations
A waterproof jacket and sturdy footwear are recommended this afternoon and evening, especially with showers and thunderstorm risk. Keep an umbrella handy, but avoid using it in lightning or strong winds.
For Friday, dress in layers as temperatures rise to 23°C, but keep rain gear nearby. By the weekend, lighter spring clothing will be comfortable as sunshine returns.
Weather Trivia
Thunderstorms can produce strong downdrafts that push air rapidly toward the ground. When that air spreads out at the surface, it can create sudden damaging wind gusts even before heavy rain reaches your location.
