Toronto awoke to thick fog and high humidity on Tuesday as Environment Canada issued a yellow-level fog advisory for the city and surrounding eastern GTA regions. The advisory remains in effect for Toronto, Pickering–Oshawa–Southern Durham, and Vaughan–Richmond Hill–Markham, warning of pockets with near-zero visibility during the morning commute.
Why it matters
The muggy conditions mark a sharp transition from summer to fall weather, disrupting transportation and signaling prolonged discomfort for residents without air conditioning as humidex values approach 36°C.
Drivers were urged to use headlights and reduce speed as mist blanketed the region before sunrise. Visibility is expected to improve later Tuesday morning. Forecasters predict a mix of cloud, sun and scattered showers throughout the day with potential thunderstorms developing. Temperatures will reach a high of 28°C, though humidity will make it feel like 36°C.
The unsettled pattern continues overnight with partly cloudy skies, thunderstorm risks and a warm low of 20°C. Wednesday brings more showers and thunderstorms with similar temperatures and even higher humidity (humidex 37°C). Relief won't arrive until Friday when drier conditions with sun and cloud are forecast.
Environment Canada has lifted the fog advisory for Halton–Peel regions where conditions cleared earlier. The weather agency continues to monitor developing thunderstorm risks across the GTA.