The summer-like weather of September 2009 will be one for the record books. With a maximum temperature of 26C Wednesday, Winnipeg registered its 17th day in September with temperatures of 25C or higher. This eclipses the previous September record of sixteen 25C days set back in 1940. And it looks like we'll add a couple more to the total before the week is through as temperatures of 25C or more are forecast both Thursday and Friday. This is in stark contrast to a very cool July, the 5th coolest on record, in which Winnipeg saw only ten days of 25C or more. In fact, September 2009 will finish with an average temperature greater than July, the first time that has ever happened in Winnipeg since records began in 1872.
The warm weather has been persistent for the past 3 weeks over southern MB with every day this month above normal so far. But changes are on the way. A storm system is expected to cross southern MB Sunday, which will draw in much cooler air Sunday into Monday on strong northwest winds. This will bring the first spell of below normal temperatures in over 3 weeks, with the risk of a widespread frost by Tuesday morning. The cool outbreak however should not be enough to offset this September finishing as the warmest September on record in Winnipeg as well as most of southern MB.