THUNDER BAY – WEATHER – Thunder Bay starts Thursday with a cool and very humid morning, sitting near 13°C at 7:00 AM EDT. The official sky condition was not observed, but the forecast is calling for a bright summer day ahead, with sunshine, a high of 28°C, and a humidex near 30.

Today’s Weather Overview

Current Conditions

At 7:00 AM EDT, Thunder Bay reported a temperature of 13.2°C. The dew point was 12.9°C, with humidity at 98 percent, giving the morning a damp, cool feel.

Winds were very light from the southwest at 2 km/h, and the barometric pressure was 101.2 kPa.

Today’s forecast is straightforward: sunny skies, a high of 28°C, and a humidex of 30. The UV index is 8, or very high, so sun protection will be important through the late morning and afternoon.

Tomorrow’s Forecast

Expected Conditions

Tonight: Clear skies are expected, with a cooler overnight low of 10°C.

Friday, July 10: Thunder Bay will see mainly sunny skies with a high of 25°C and a humidex near 26. The UV index remains 8, or very high. Friday night brings cloudy periods with a 30 percent chance of showers and a low of 11°C.

Saturday, July 11: The weekend begins with a mix of sun and cloud and a 30 percent chance of showers. The high will reach 27°C. Saturday night remains partly unsettled, with cloudy periods, a 30 percent chance of showers, and a low of 14°C.

Sunday, July 12: Warmer air returns with a mix of sun and cloud, a 30 percent chance of showers, and a high of 30°C. Sunday night brings cloudy periods with a 30 percent chance of showers and a mild low of 17°C.

Wardrobe Recommendations

Start the day with a light sweater or jacket if you are out early, especially with the damp morning air. By afternoon, light summer clothing will be the best choice.

With the UV index at 8, use sunscreen, wear sunglasses, and consider a wide-brimmed hat. Keep water handy if you are working or exercising outdoors, especially as temperatures climb into the upper 20s.

Weather Trivia

Thunder Bay can see cool, damp mornings followed by warm afternoons during July. Light winds, high humidity, and nearby Lake Superior can keep the morning feeling fresh before inland warmth builds later in the day.

Overview: Thunder Bay weather for July 9, 2026: cool and humid 13°C morning, sunny skies, high 28°C, humidex 30, very high UV, clear tonight, and warm weekend weather ahead.