Its just after 7AM, the temperature dropped to -41C before midnight.
Yellowknife, NT - 7 Day Forecast - Environment Canada
WEATHER.GC.CA
Current conditions and forecasts including 7 day outlook, daily high/low temperature, warnings, chance of precipitation, pressure, humidity/wind chill (when applicable) historical data, normals, record values and...
The above link will show the current weather at the time it is clicked on, here is my weather at 7AM my local time:
Condition:Mist, Pressure:101.9 kPa, Tendency:Falling
Temperature:-41.7°C, Dew point:-45.5°C, Humidity:67%
Wind:NE 11 km/h, Wind Chill:-54, Visibility: 2 km