...The coldest I ever operated in was -35c in Calgary. Even though the bird got parked in the hanger overnight, just sitting on the ramp for an hour before we arrived played havoc....
Coldest for ME was working on the ramp ('baggage-basher') at Edmonton International ('65 or '66) - temp was -40F w/ a 40 mph wind - the radio gave the wind-chill as being -108F.
We had a DC8 come in from YVR, (pre loading-bridges) and because the engines couldn't be started when they were turning-over, the aircraft was turned left-wing into wind, so PAX were walking down the stairs INTO that wind, MOST dressed for Vancouver weather.
We had a 'cab-over' Ford heater plugged-in, facing the wind, engine running, and when I tried to move it so the DC8 could leave, even tho' it was toasty-warm in the cab - the power-steering had frozen, so I backed it up about half a mile to get into the lee of the buildings, then waited till I could turn the wheel to park it inside, in the concourse.
During my 37 years as a pilot, the COLDEST I remember was during 'advanced jet training' on the T-33 at CFB Moose Jaw, in Saskatchewan. NO idea of the temp, but I finished the walk-around, got in, strapped-in, then (because IF you attached your O2 mask BEFORE you set take-off power, you would freeze the valves in it) sat there waiting for a non-com to pull over a power unit and "start me", the Tbird parked at 90 degrees to the wind, so it was HOWLING across my face, the ONLY respite being the collar of my winter flying-suit pulled UP....
Operationally, I flew all over the Arctic in the RCAF (including over the true North Pole), as well as Canada in winter-time - both airforce and airline, and THAT T-33 episode sticks in my mind as the COLDEST...!
Later, after a tour flying C-130s, I was told that my next tour was instructing at Moose Jaw, so I put in my resignation from the RCAF - joining Air Canada!!!