Environment Canada has issued a severe thunderstorm watch for a portion of the Golden Horseshoe which includes Hamilton, Niagara Region, Caledonia, and Brantford.
The weather agency says thunderstorms are expected to move across the region Thursday morning that could bring heavy rain and wind gusts of 90 kilometres per hour.
Very strong wind gusts can damage buildings, down trees and blow large vehicles off the road, according to the agency.
The Office of the Fire Marshal and Emergency Management suggests that residents take cover immediately if threatening weather approaches.