Thunder Bay Midweek Weather: From Clouds to Sun and Warm Breezes

THUNDER BAY – Wednesday, July 2, 2025 – The day begins on a calm and mostly cloudy note in Thunder Bay, with current conditions sitting at 14°C. The temperature is rising steadily, with a barometric pressure of 101.1 kPa also on the rise. Humidity is high at 89%, making the air feel slightly damp. Winds are light out of the west at 4 km/h, and visibility is an impressive 32 km—clear views across the Sleeping Giant this morning!

Clearing Skies and a Comfortable Summer Day Ahead

Don’t let the morning clouds fool you—sunshine is on its way. Skies will clear late this morning as westerly winds pick up to 20 km/h, gusting to 40 km/h by midday. Temperatures will climb to a warm high of 27°C with a modest humidex reading of 29. With a UV index of 8, rated “very high,” it’s a sunscreen and sunglasses kind of day.

Tonight, skies remain crystal clear with a refreshing breeze from the northwest at 20 km/h, diminishing to light winds as the night sets in. Overnight low dips to a comfortable 10°C—great sleeping weather, and maybe even cool enough to crack a window.

Sunshine Stays for Thursday, but Rain Creeps In by Friday

Thursday looks idyllic, with full sun and a high of 25°C. The humidex will only slightly elevate the feel to 26, but the UV index climbs again to a very high 9. Thursday night remains clear with a mild low of 12°C.

Friday brings a mix of sun and cloud, along with a 40% chance of showers and a high of 24°C. Expect increasing cloudiness and another 40% chance of overnight showers with a low of 18°C.

Saturday is shaping up to be wetter, with a 60% chance of showers during both day and night and a daytime high of 24°C.

What to Wear and Watch For

Today’s wardrobe winner? Light layers and a good sunhat. It may start cool, but with sunshine and mild breezes ahead, it’s a great day to get outdoors—but don’t skip the sunscreen. Keep an umbrella close by starting Friday just in case the forecasted showers roll in early.

Weather Trivia: Thunder Bay is no stranger to fast-changing weather thanks to its proximity to Lake Superior. This massive freshwater lake can rapidly alter wind and temperature patterns, giving the city some of the most dynamic weather in the province.