The jet stream acts as a barrier to arctic air masses - primarily high pressure (clock is high on the wall = clockwise) air masses that mean cold air.
Today (13/02/2016) I noticed the temperature dipped to -28c (-19f) - which means a 50c (90f) difference between the walls of our house.
My FLIR camera is required to get a correspondence second reading - unfortunately it is not made for Canadian weather. The FLIR will work in Alaska along the coast which is warmer than us today.
The canal will be excellent for skating today - except for the wind chill which at 20kph may mean close to -45c temps.