Environment Canada has issued a severe thunderstorm watch for Hamilton for Wednesday afternoon and into the evening.
Conditions are brewing for the development of storms that could produce strong winds and large hail.
Environment Canada warns that hail can damage property and cause injuries, while strong wind gusts can toss around loose objects, damage weak buildings and and overturn large vehicles.
Severe thunderstorms can also produce tornadoes. Hamilton was under a tornado two weeks ago.
“Stay indoors when a thunderstorm strikes,” Environment Canada says. “There isn't a place outside that is safe during a thunderstorm. In Canada, lightning kills up to 10 people every year.”