Toronto averages about 830 mm (roughly 33 inches) of precipitation a year, spread fairly evenly across the seasons between rain and, in winter, a mix of rain and snow off Lake Ontario. Summer brings the highest risk of sudden, intense thunderstorms, some capable of producing damaging wind and hail as warm, humid air moves up from the Great Lakes and collides with cooler fronts. Because the city’s storm sewer system dates back many decades in older neighborhoods, short bursts of heavy rain can overwhelm drainage faster than the total rainfall would suggest, leading to localized flooding on major roads and underpasses. Lake-effect weather also means conditions can shift quickly near the shoreline compared with areas further inland. Environment Canada’s weather radar network covers the Greater Toronto Area, giving residents a practical way to see an approaching squall line or lake-effect band before it reaches downtown.
Learn more: How Does Rain Radar Work? · Open the full Rain Map