Although daytime temperatures were only a few degrees below normal in Winnipeg on the coldest days in mid September, they fell quite rapidly at night. On a few days, the difference in temperature between night and day was more than 20 degrees! This may have been thanks to very dry soil conditions which helped accelerate heat loss from the ground at night.
The growing season at the airport ended on September 14 with a low of -1.0°C, about a week earlier than normal (Sep 22). This puts the length of the 2012 growing season at 106 days, shorter than the normal of 121 days. Of note however, this value for 2012 is a little misleading considering the ideal growing conditions seen this year due to a very warm Spring. By using the number of days between hard frosts instead (hard frost is defined as a night of -2°C and colder) we get a season of 148 days for 2012 (Apr 27 to Sep 21 inclusively). That is much more representative of the conditions experienced this year.
|Snow in Kenora Sep 21|
The cold spots were Dugald at -9°C and Emerson and Fisher Branch at -8.5°C. Some official record low temperatures across the province included:
In total, 7 days had a low below zero in Winnipeg, tying for third most subfreezing days on record for September. Click here for a graph demonstrating the frequency of days with a subfreezing low in September since 1872.
This post contains pictures, videos or information from the following sources
The Weather Network
Environment Canada Weatheroffice