Thunder Bay weather for June 19, 2026: mainly sunny and cool near 7°C this morning, increasing cloudiness later today, a high of 21°C, and showers likely Saturday.
Thunder Bay – WEATHER – Thunder Bay begins Friday with a crisp but bright morning, as mainly sunny skies and rising pressure bring a calmer start to the day. Temperatures are cool near 7°C, but conditions will warm steadily, with cloud cover expected to increase late this morning.
Today’s Weather Overview
Current Conditions
As of 6:00 AM EDT at Thunder Bay Airport, the temperature is 7.1°C, with a dew point of 6.1°C. Humidity is high at 93%, giving the early morning air a cool and slightly damp feel.
Winds are from the southwest at 13 km/h, visibility is excellent at 32 kilometres, and the barometric pressure is 101.1 kPa and rising. That rising pressure supports the mainly sunny start, although clouds will move in as the morning progresses.
Today’s forecast calls for sunny skies early, followed by increasing cloudiness late this morning. The daytime high will reach 21°C, and the UV index is 7, rated high.
Tonight will be partly cloudy, becoming cloudy late this evening, with an overnight low of 10°C.
Tomorrow’s Forecast
Expected Conditions
Saturday will bring a more unsettled pattern to Thunder Bay. Expect mainly cloudy skies, with a 30 percent chance of showers early, increasing to a 70 percent chance of showers late in the morning. There is also a risk of a thunderstorm in the afternoon.
Saturday’s high will be 17°C, and the UV index will be 5, rated moderate. Saturday night will bring cloudy periods with a 40 percent chance of showers and a low of 7°C.
Sunday will offer a mix of sun and cloud, along with a 40 percent chance of showers. The high will climb to 20°C, followed by cloudy periods overnight and a cool low of 6°C.
Monday looks warmer, with a mix of sun and cloud, a 30 percent chance of showers, and a high of 23°C. Monday night will bring cloudy periods and a low of 8°C.
Wardrobe Recommendations
A sweater or light jacket is a good choice early this morning, especially with temperatures near 7°C. By afternoon, lighter layers should be comfortable as the temperature rises toward 21°C.
Sunglasses and sunscreen are recommended today because the UV index is high, even with clouds increasing later in the morning. For Saturday, keep a rain jacket or umbrella nearby, as showers become more likely and there is a risk of afternoon thunderstorm activity.
Weather Trivia
Thunder Bay’s June weather often shows the balancing act between inland warmth and Lake Superior’s cooler influence. Even when afternoons climb into the low 20s, mornings can still feel chilly and damp, especially when humidity is high and winds move across cooler lake-influenced air.
