The city with the coldest winters, according to the average nighttime temperature during December, January and February, is Yellowknife at -29.9 degrees Celsius (-21.8 degress Fahrenheit). It is also the coldest city with a mean annual temperature of -5.4 degrees Celsius (22.3 degress Fahrenheit). Yellowknife, however, has the sunniest summers with the most hours of sunshine during June, July and August with an average of over 1037 hours.