Forecast models from Environment Canada and private sources indicate Toronto will see a daytime high near 25°C under mostly sunny skies on August 21, followed by clear overnight conditions favoring radiational cooling and a minimum near 16°C. Light winds and low humidity support efficient heat loss after sunset, while recent regional warmth has kept the airmass mild enough to limit deeper cooling. Trader consensus clusters tightly around 13–16°C because small variations in cloud cover timing or wind speed can shift the low by 1–2°C, and official Environment Canada guidance places the expected minimum in this narrow range with modest uncertainty remaining until final observations are recorded.