Because of the generally flat landscape, it is exposed to cold Arctic high-pressure air masses from the northwest during January and February.
In the summer, air masses sometimes come out of the Southern United States, as warm humid air is drawn northward from the Gulf of Mexico.
Temperatures exceed 30 °C  numerous times each summer, and the combination of heat and humidity can bring the humidex value to the mid-40s.
Carman, Manitoba, recorded the second-highest humidex ever in Canada in 2007, with 53.0.