Northern Canada is enduring a harsh cold spell, with temperatures between -20C and -40C for weeks. On Tuesday, Braeburn in Yukon recorded a bone-chilling -55.7C, its coldest December temperature since 1975. Mayo and Dawson saw 16 straight nights below -40C, with Mayo dropping to -50.4C on Monday. Whitehorse had 10 nights below -30C. This cold blast extended south during Christmas, with Edmonton dropping below -28C overnight on Christmas Day and lows of around -20C expected in several cities including Montreal, Ottawa, and Quebec on Boxing Day. Officials warn Yukon faces electricity outages as energy demand hits record highs. The deep freeze is caused by the polar vortex sitting over Canada all December, bringing Arctic air south. Next week, milder Pacific air is expected to push the cold north. Meanwhile, the US experienced its warmest Christmas ever, with temperatures 15-30C above the norm. Oklahoma City reached 25C, beating the old record of 22C from 1982. Cities like Austin, Dallas, and Charlotte also saw temps over 25C. Warmth is forecast to continue, fueled by a heat dome caused by a strong ridge of high pressure trapping heat near the surface. This pattern compresses the air and boosts temperatures, creating spring-like warmth in winter.