About 51,000 Hydro-Quebec customers were still without electricity by late afternoon, compared with 350,000 on Friday.
The Laurentian Mountains, the Monteregie region, and the Montreal area were the hardest hit, where strong gusts brought down trees and sent chunks of debris flying.
In Ontario, the central and eastern parts of the province took the brunt of the damage.
Hydro One says 37,000 customers were without power by late afternoon, down from 126,000 on Friday.
The utility says it expects the work to continue through the weekend.