temperature in toronto canada in september
1 Overnight temperatures are generally mild with an average low of 12.6 Â°C (54.7 Â°F). 2  In September the mean daily temperature range/ variation is 7.4 Â°C (13.3 Â°F). 3  The weather in September is somewhat dry with rain at times. 4  Just 75.5mm (3in) of liquid is released during an average of 10 days.