12:11 p.m. EDT Saturday 18 July 2026

Impact Level: High

Forecast Confidence: Moderate


Localized poor air quality and reduced visibility due to smoke from wildfires in northwestern Ontario will continue today. Poor air quality may persist into tonight.

A major improvement is expected on Sunday.

Air quality and visibility due to wildfires smoke can change rapidly over short distances and from hour to hour.

As smoke levels increase, health risks increase. Limit time outdoors. Consider reducing or rescheduling outdoor sports, activities and events.

You may experience mild and common symptoms such as eye, nose and throat irritation, headaches or a mild cough. More serious but less common symptoms include wheezing, chest pains or severe cough. If you think you are having a medical emergency, seek immediate medical assistance.

People more likely to be impacted by wildfire smoke, including people aged 65 and older, pregnant people, infants and young children, people with an existing illness or chronic health condition, and people who work outdoors, should reduce or reschedule strenuous activities outdoors and seek medical attention if experiencing symptoms.

When indoors, keep windows and doors closed as much as possible. When there is an extreme heat event occurring with poor air quality, prioritize keeping cool.

Protect your indoor air from wildfire smoke. Actions can include using the highest quality air filter that your ventilation system can handle and/or a certified portable air cleaner that can filter fine particles.

If you must spend time outdoors, a well-constructed, well-fitting and properly worn respirator type mask (such as a NIOSH-certified N95 or equivalent respirator) can reduce your exposure to the fine particles in the smoke. Even though exposure may be reduced, there can still be risks to health.

Check in on others who are in your care or live nearby who may be more likely to be impacted by wildfire smoke.

Always follow guidance from local authorities.

Learn more at https://www.canada.ca/wildfire-smoke.

For further information visit the website https://www.airqualityontario.com/ or contact the Ontario Ministry of the Environment, Conservation and Parks at 416-314-6666.

Visit http://www.airhealth.ca for information on how to reduce your health risk and your personal contribution to pollution levels, as well as for current and forecast AQHI values.

Please continue to monitor alerts and forecasts issued by Environment Canada.

Issued by Environment Canada and the Province of Ontario

In effect for:

• Pickering - Oshawa - Southern Durham Region

9:01 a.m. EDT Saturday 18 July 2026

Impact Level: Moderate

Forecast Confidence: High


Conditions are favourable for the development of severe thunderstorms that may be capable of producing strong wind gusts, large hail and heavy rain.

What:
Wind gusts up to 110 km/h.
Quarter to ping pong ball sized hail.
Rainfall amounts 25 to 40 mm.

When:
Beginning near noon into this afternoon.

Additional Comments:
A cold front over Michigan is expected to bring a line of thunderstorms as it moves southeast over the area today. The strongest thunderstorms are expected early this afternoon.

Driving conditions may be difficult. Local utility outages are possible. Damage to roofs, fences, branches or soft shelters is possible.

When thunder roars, go indoors! Lightning kills and injures Canadians every year. Secure loose objects.

Emergency Management Ontario recommends that you take cover immediately if threatening weather approaches.

Heavy rain can cause flash flooding and significant reductions to visibility. Severe thunderstorm watches are issued when conditions are favourable for the development of thunderstorms capable of producing damaging hail, wind or rain.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ONstorm@ec.gc.ca or post reports on X using #ONStorm.

For more information: https://www.ontario.ca/page/be-prepared-emergency.

In effect for:

• Pickering - Oshawa - Southern Durham Region