The orange haze in Ontario and northern US is caused by wildfires in Canada.

Well-supported — high-quality sources agree

What we can confirm

Authoritative meteorological agencies, space agencies, and major news outlets report that recent orange or gray-yellow haze over Ontario and the northern United States has been caused by smoke from large wildfires burning in Canada, whose particles refract sunlight and change the apparent color of the sky; alternative explanations such as chemical releases have been specifically rejected by experts.

Sources

Checked July 17, 2026 · we'll re-check as this develops