THUNDER BAY – WEATHER – Tuesday is starting cool and damp across Thunder Bay, with mostly cloudy skies, high humidity, and fog patches lingering early this morning. The day ahead will stay on the grey side, with a chance of showers and a daytime high that remains below the usual mid-June feel.
The good news: the forecast improves later in the week. After a cloudy and unsettled Tuesday, Wednesday brings a mix of sun and cloud, Thursday carries another shower chance, and Friday looks like the standout day with sunshine and a high near 21°C.
Today’s Weather Overview
Current Conditions
As of 8:00 AM EDT Tuesday, June 16, 2026, Thunder Bay is reporting mostly cloudy skies with a temperature of 9.8°C.
The air is quite moist, with humidity at 92 percent and a dew point of 8.6°C. That explains the cool, damp morning feel and the fog patches noted in the forecast.
Barometric pressure is 100.3 kPa and falling, suggesting the atmosphere remains unsettled. Winds are light from the west-northwest at 6 km/h, and visibility is excellent at 32 kilometres.
For today, expect mainly cloudy skies with a 40 percent chance of showers. Fog patches will dissipate this morning. The high will reach only 16°C, but the UV index is 7, or high, meaning sun protection is still important if brighter breaks develop.
Tonight’s Forecast
Tonight will be partly cloudy, with a 40 percent chance of showers this evening. Temperatures will fall to a cool overnight low of 7°C.
It will be a good evening to keep a light jacket or hoodie handy, especially if you are out walking, cycling, or spending time near the waterfront.
Midweek Forecast
Wednesday, June 17
Wednesday offers some improvement, with a mix of sun and cloud and a high of 17°C. The UV index remains 7, or high, so do not let the cooler temperature fool you. Sunscreen, sunglasses, and a hat are still smart choices during sunny breaks.
Wednesday night turns cloudy, with a low near 7°C.
Thursday, June 18
Thursday brings another unsettled day, with cloudy skies and a 40 percent chance of showers. The high should climb to 20°C, making it milder than Tuesday and Wednesday.
Thursday night will feature cloudy periods with a 30 percent chance of showers and a low of 9°C.
Friday and Weekend Outlook
Friday currently looks like the best day of the week. The forecast calls for sunny skies and a high of 21°C. Friday night should be clear, with a low near 9°C.
Saturday and Sunday both look pleasant and seasonable, with a mix of sun and cloud and daytime highs near 21°C. Overnight lows will sit around 8°C, keeping evenings cool but comfortable.
Monday, June 22, continues the fair-weather trend with a mix of sun and cloud and a high near 22°C.
Weather Alerts
No specific weather alert information was included in the supplied Thunder Bay forecast details. Residents should continue checking Environment Canada updates if showers intensify or if conditions change through the day.
Wardrobe Recommendations
Tuesday calls for layers. A hoodie, light jacket, or fleece will feel right this morning, especially with temperatures near 10°C and high humidity. Keep a rain jacket nearby for passing showers, but heavy rain is not the main story today.
For Wednesday and Thursday, continue dressing for cool mornings and milder afternoons. By Friday and the weekend, lighter daytime clothing should be comfortable, but evenings will still call for a sweater or jacket.
Even with cloud in the forecast, the UV index is high today and Wednesday, so sunglasses and sunscreen remain important.
Weather Trivia
Thunder Bay’s cool June mornings are often influenced by Lake Superior, which warms slowly in spring and early summer. When moist air moves across or near the lake, the city can see cooler temperatures, fog patches, and low cloud, even while inland locations warm more quickly.
