Thunder Bay starts Wednesday under smoky skies, with two weather alerts still in effect: a Yellow Heat Warning and a Yellow Air Quality Warning. At 7:00 AM EDT, the temperature was 19.2°C, with smoke reducing visibility to 4 km.
The heat event is expected to end this evening as a cooler, less humid air mass moves into the region. However, wildfire smoke may continue to affect air quality into Thursday for some areas.
Today’s Weather Overview
Current Conditions
At 7:00 AM EDT, Thunder Bay reported smoke with a temperature of 19.2°C. The dew point was 11.8°C, with humidity at 62 percent.
Winds were from the west at 10 km/h, visibility was reduced to 4 km, and the barometric pressure was 101.9 kPa and rising.
Today’s forecast calls for sunny skies, becoming a mix of sun and cloud this afternoon. Widespread smoke will become local smoke early this morning. Winds will become north at 20 km/h, gusting to 40 km/h this morning. The high will reach 28°C, and the UV index is 9, or very high.
Weather Alerts in Effect
Yellow Warning — Heat
Impact Level: Moderate
Forecast Confidence: High
A heat event continues today for the City of Thunder Bay, with maximum temperatures near 29°C and minimum temperatures of 17°C to 20°C.
The heat warning is expected to end this evening as cooler, less humid air moves in. Until then, residents should continue taking precautions, especially older adults, young children, outdoor workers, people living alone, and anyone with health conditions.
Yellow Warning — Air Quality
Impact Level: Moderate
Forecast Confidence: High
Wildfire smoke is causing poor air quality and reduced visibility. Poor air quality may persist into Thursday for some areas.
Smoke can cause eye, nose, and throat irritation, headaches, and mild coughing. More serious symptoms may include wheezing, chest pain, or severe cough. Anyone experiencing a medical emergency should seek immediate medical help.
People most likely to be affected include seniors, pregnant people, infants, young children, people with chronic health conditions, and those who work outdoors.
Tomorrow’s Forecast
Expected Conditions
Tonight: Skies will be clear with local smoke. Northwest winds at 20 km/h will become light this evening. The overnight low will be 18°C.
Thursday, July 16: Thunder Bay will see sunny skies, then increasing cloudiness early in the afternoon. Local smoke remains in the forecast. The high will reach 26°C, with a humidex of 28 and a UV index of 8, or very high. Thursday night turns cloudy with a 30 percent chance of showers and a low of 12°C.
Friday, July 17: Expect cloudy skies with a 40 percent chance of showers and a high of 24°C. Friday night remains cloudy with a 30 percent chance of showers and a low of 12°C.
Saturday, July 18: Conditions improve with clearing skies and a high of 26°C. Saturday night will be clear, with a low of 13°C.
Health and Safety Advice
When heat and wildfire smoke happen at the same time, the priority is to stay cool while limiting smoke exposure.
Keep windows and doors closed as much as possible when smoke is heavy. Use air conditioning or a portable air cleaner if available. If your home becomes too hot, move to a cooler indoor space such as a library, community centre, mall, or cooling location.
Drink water often, even before feeling thirsty. Watch for signs of heat exhaustion, including headache, nausea, dizziness, thirst, dark urine, and intense fatigue. Heat stroke is a medical emergency. Call 911 if someone has red, hot skin, confusion, dizziness, nausea, or a change in consciousness.
Wardrobe Recommendations
Wear lightweight, light-coloured, loose-fitting clothing today. A wide-brimmed hat, sunglasses, and sunscreen are important with the UV index at 9.
If you must spend time outdoors in smoke, reduce strenuous activity. A well-fitting N95-style respirator can reduce exposure to fine particles, though it does not remove all risk.
Weather Trivia
Wildfire smoke can reduce visibility and make the sky look hazy or orange, but UV levels can still remain very high. That means sunscreen and sun protection are still important even when the sun appears dimmed by smoke.
Summary: Thunder Bay weather update for July 15, 2026: Yellow Heat Warning and Yellow Air Quality Warning remain in effect, with smoke, 19°C early, high 28°C, very high UV, and cooler air arriving tonight.
