Smoke Alert Continues – Likely to End Later Today

Thunder Bay – WEATHER DESK – Thunder Bay begins Saturday under widespread wildfire smoke, sharply reduced visibility and an Orange Air Quality Warning. The temperature is already near 19°C, with a humid afternoon expected as the high reaches 26°C.

A chance of showers and thunderstorms could bring temporary local improvement, but Environment Canada expects very poor air quality to continue through much of the weekend.

The Smoke Advisories for Fort Frances and Dryden have ended. It is possible that with changing conditions, the advisory currently in effect for Thunder Bay could end as well by later today or Sunday.

The Wildfire Situation continues to impact local conditions.

Today’s Weather Overview

Current Conditions

At 6:38 a.m. EDT on Saturday, July 18, the temperature at Thunder Bay was 19.1°C.

The dew point was 16.3°C, with humidity at 84 per cent, creating a warm and slightly muggy start to the day.

Winds were from the north-northwest at 15 km/h, gusting to 28 km/h. They are forecast to strengthen from the north to 20 km/h, with gusts reaching 40 km/h later this morning.

Barometric pressure was 101.0 kPa and rising.

Visibility was reduced to only two kilometres because of wildfire smoke. Drivers should use extra caution, particularly on highways and rural roads where visibility may change quickly.

Thunder Bay will remain mainly cloudy today. There is a 40 per cent chance of showers early this morning, along with a risk of a thunderstorm.

Widespread smoke will continue throughout the day. The temperature will reach 26°C, with a humidex value of 27.

The UV index will be 7, or high. Sunscreen and other sun protection remain necessary even when smoke and cloud obscure the sky.

Orange Air Quality Warning

An Orange Air Quality Warning remains in effect for the City of Thunder Bay. The alert has a high impact level and high forecast confidence.

Wildfire smoke from northwestern Ontario is producing very poor air quality and reduced visibility. Conditions can change quickly over short distances and from one hour to the next.

During periods of heavy smoke, everyone may experience health effects, regardless of age or general health.

Common symptoms can include:

• Irritated eyes, nose or throat
• Headaches
• A mild cough

Less common but more serious symptoms can include wheezing, chest pain or a severe cough. Anyone who believes they are experiencing a medical emergency should seek immediate medical assistance.

People more likely to be affected include adults aged 65 and older, pregnant people, infants, young children, people with chronic health conditions and those who work outdoors.

Outdoor sports organizers, coaches and event officials should assess local air quality before proceeding. The intensity of the activity and the needs of participants and spectators should be considered.

Residents should limit time outdoors and avoid strenuous activity when smoke is heavy. Keep windows and doors closed where practical, and use a certified portable air cleaner or the highest-quality filter suitable for the home ventilation system.

A properly fitted NIOSH-certified N95 or equivalent respirator can reduce exposure to fine smoke particles when outdoor activity cannot be avoided. It does not eliminate all health risks.

Tonight’s Forecast

Widespread smoke will continue tonight.

The overnight low will fall to 14°C. No significant precipitation is mentioned in the overnight forecast, but air quality and visibility may remain poor.

Anyone opening windows to cool their home should first consider the outdoor smoke conditions. During warm weather combined with poor air quality, maintaining a safe indoor temperature remains important.

Extended Forecast

Sunday, July 19

Sunday will bring a mix of sun and cloud, with widespread smoke continuing across the Thunder Bay area.

There is a 30 per cent chance of showers during the afternoon, along with a risk of a thunderstorm.

Winds will be from the east at 20 km/h before becoming southerly at 20 km/h during the afternoon.

The temperature will reach 27°C, with a humidex value of 31. The combination of heat, humidity and smoke could make prolonged outdoor activity uncomfortable.

The UV index will rise to 8, or very high.

Sunday night will bring cloudy periods and a 40 per cent chance of showers. The overnight low will be 17°C.

Monday, July 20

Monday will feature a mix of sun and cloud, with a 40 per cent chance of showers.

The daytime high will reach 26°C.

Cloudy periods and a 40 per cent chance of showers will continue Monday night, with a low of 15°C.

Tuesday, July 21

Tuesday will be cooler, with a 30 per cent chance of showers and a daytime high of 21°C.

Cloudy periods are expected Tuesday night as the temperature falls to 11°C.

Wardrobe Recommendations

Lightweight and breathable clothing will be most comfortable Saturday and Sunday as temperatures climb into the mid-to-upper 20s.

A light rain jacket or compact umbrella may be useful because of the risk of showers. Do not use an umbrella during nearby lightning.

An N95 or equivalent respirator should be considered when outdoor activity cannot be avoided, particularly while smoke remains dense.

People heading outside should also carry water and use sunscreen, sunglasses and a wide-brimmed hat. Sunday’s very high UV index means unprotected skin can burn quickly.

Drivers should keep headlights on when visibility is reduced and allow extra stopping distance.

Weather Trivia

Wildfire smoke can travel hundreds or even thousands of kilometres from its source. Fine particles can remain suspended in the atmosphere and may be carried into communities far from an active fire.

Changes in wind speed and direction can cause air quality and visibility to improve or deteriorate rapidly. This is why one part of Thunder Bay may experience thicker smoke than another at the same time.

Source: Environment Canada observations at 6:38 a.m. EDT and forecast issued at 5:30 a.m. EDT on Saturday, July 18, 2026. Air quality warning issued by Environment Canada and the Province of Ontario.

Overview: Thunder Bay begins July 18 under dense wildfire smoke with visibility reduced to two kilometres. An Orange Air Quality Warning remains in effect as temperatures rise to 26°C with possible showers and thunderstorms.