The city of Toronto continued to be under a heat alert and a severe thunderstorm watch Sunday evening after a day of erratic weather.

Race fans worried about the Grand Prix going ahead full-speed as rain poured down on the city earlier in the day, and artists at an exhibition at Nathan Philips Square scrambled to preserve their work.

After the storm, Environment Canada warned more extreme weather could be in store for Southern Ontario.

Severe thunderstorms could also form, bringing:

  • Large hail;
  • Heavy rain;
  • Deadly lightning; or
  • Damaging winds.

Residents under the watch should secure loose objects, shelter animals and make sure family members or co-workers are ready to deal with extreme weather.

Whether or not Sunday night brings another storm, temperatures certainly soared during the day -- and health officials warned people not to be fooled by the clouds.

"Despite the wet weather, the heat alert issued earlier (Sunday) remains in effect," said Elaine Pacheco, a manager with Toronto Public Health.

"People really need to take it easy and slow whenever hot weather is around in the summer."

Torontonians enjoying the outdoors during heat alerts can take the following precautions to avoid heat-related illness:

  • Drink lots of water and natural fruit juices even if you don't feel very thirsty;
  •  Avoid alcoholic beverages, coffee and cola;
  • Wear loose fitting, light clothing, and a hat;
  • Avoid intense or physical activity; and
  • Never leave a child in a parked car or asleep in direct sunlight.

The city encourages people who feel affected by the heat during the summer to visit shopping malls or go to one of over 190 local library branches or air-conditioned community centres in the city to cool down.

With a report from CTV's Mairianna Bachynsky