Environment Canada says people should be prepared for severe thunderstorms that could bring some wild weather to southwestern Ontario on Sunday.
Its meteorologists say the storm is capable of producing hail of up to two centimetres in diameter. It may also produce heavy rain — up to 50 millimetres in an hour.
Wind gusts may also be strong, clocking in at up to 90 km/h this afternoon and this evening, with rain most likely later this evening.
On top of the severe thunderstorm watch, a heat warning continues.
Temperatures are expected to hit daytime highs of between 29 and 32 C, with humidex values of 37 to 42.
Overnight lows will be between 20 and 23 C.