The agency said strong southwest winds will develop Sunday morning or early Sunday afternoon as a cold front moves through southern Ontario.
The warning said very strong wind gusts near 90 km/h are expected, with possible localized gusts of more than 100 km/h.
“Isolated thunderstorms are possible along this cold front, which may bring localized wind gusts in excess of 100 km/h,” the warning reads.
The agency said that “widespread power outages may occur,” and that loose objects may be tossed by the wind and could cause damage or injury.
“Be prepared to adjust your driving with changing road conditions due to high winds,” the warning reads.
According to Environment Canada, winds will “gradually ease” by Sunday evening.
In a tweet Sunday afternoon, Toronto police said the force has received “many reports of blowing debris, wires down and toppled trees” due to the high winds.