Heat Warnings Expand to Ontario, Northeast U.S.

Heat warnings and advisories have been issued by Environment Canada and the U.S. National Weather Service for large parts of Canada—including Ontario, Manitoba, and the Maritimes—and the northeastern United States. Southern Ontario, including Toronto and Waterloo, is experiencing humidex values up to 40°C, with minimal relief at night, leading to heightened health risks. The Maritimes and P.E.I. are facing similar conditions, as temperatures near 30°C feel closer to 37°C due to high humidity. Southern Manitoba is also under a heat warning, with particular concern for vulnerable populations. In the northeastern U.S., advisories cover areas such as northern Connecticut, where heat index values approach 36°C (96°F) and elevated ground-level ozone poses additional health risks. Authorities urge residents to stay hydrated, avoid strenuous activities, and watch for symptoms of heat-related illnesses.