Tornado climatology
The United States averaged 1,274 tornadoes per year in the last decade. April 2011 saw the most tornadoes ever recorded for any month in the US National Weather Service's history, 875; the previous record was 542 in one month. It has more tornadoes yearly than any other country and reports more violent (F4 and F5) tornadoes than anywhere else.
List of Canadian tornadoes and tornado outbreaks
Ontario, Alberta, Manitoba and Saskatchewan all average 15 tornadoes per season, followed by Quebec with fewer than 10. New Brunswick and the British Columbia Interior are also recognized tornado zones. All other provinces and territories have significantly less threat from tornadoes. The peak season in Canada is in the summer months when clashing air masses move north, as opposed to the spring season in the United States southern-central plains, although tornadoes in Canada have occurred in spring, fall and very rarely winter.