THUNDER BAY – WEATHER DESK – Thunder Bay starts Thursday with a cool, damp feel and a mainly cloudy forecast ahead. Showers are likely through the day and into tonight, with a risk of thunderstorms as the city moves through an unsettled early-June weather pattern.
Today’s Weather Overview
Current Conditions
At 7:00 AM EDT Thursday, June 4, 2026, Thunder Bay was sitting at 10.8°C. The reported condition was not observed, but the weather setup points to a cloudy and unsettled morning.
The dew point is 6.1°C, with humidity at 73 percent. Winds are from the east-northeast at 11 km/h, and the barometric pressure is 101.5 kPa.
Today will be mainly cloudy with a 60 percent chance of showers and a risk of a thunderstorm. The high will reach 19°C, with a UV index of 6, or high.
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 a thunderstorm. The overnight low will be 11°C.
Friday, June 5: Conditions improve slightly, but the shower risk remains. Expect a mix of sun and cloud with a 40 percent chance of showers and 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: Cloudy periods are expected with a 30 percent chance of showers and a low of 10°C.
Saturday, June 6: The weekend begins on a calmer note, with a mix of sun and cloud and a high of 21°C. Saturday night will be clear, with a low of 9°C.
Sunday, June 7: Sunshine returns more fully, with a forecast high of 26°C. Sunday night will be clear with a low near 12°C.
Wardrobe Recommendations
A light rain jacket or umbrella is a smart choice today and tonight, especially with showers and possible thunderstorms in the forecast. Temperatures will stay mild, so a spring jacket should be enough for most of the day.
For Friday, dress in layers. It will be warmer at 23°C, but the afternoon thunderstorm risk means outdoor plans should include a quick way to get indoors. By the weekend, lighter spring clothing will be comfortable, especially Sunday when sunshine and 26°C weather arrive.
Weather Trivia
Thunder Bay’s weather can shift quickly in early June because Lake Superior remains cool while inland areas warm. That temperature contrast can help keep parts of the city cooler near the waterfront, while also adding moisture and instability when showers move through the region.
