While Northern Plains, Great Lakes region and Upper Midwest are experiencing with severe blizzard already, which will be replaced by extreme frosts during next hours /article about measured extremes already in next series of articles on Mkweather: https://mkweather.com/2020/12/20/usa-with-abnormal-christmas-windchill-50f-45c-one-of-the-coldest-christmas-since-2000//, southern USA, before an arrival of powerful cold front is reporting extremely hot Christmas weather, with summer temperatures in Texas or Florida and wildfires in California.
In Austin City and Del Rio, maximum temperatures have reaches summer 82°F / +27,8°C last 24 hours, Houston has reported 81°F / 27,1°C and Miami 79°F / +26,1°C.
In California, thanks to Santa Ana winds, isn´t so hot such as in southern USA, but near autumn temperatures, extremely drought, sun and severe winds, wildfire situation is again critical mainly in southern California.
Meanwhile, Key Lake, central Saskatchewan is reporting -46,7°F / -43,7°C and this extremely cold air is shifting above northern states of the USA, with reaching of extreme values of windchill index during next hour (mainly Christmas Day, 25.12.2020) up to -50°F / -45°C and possible minimum temperatures below -30°F / -35°C, maybe very rarely -40°F / -40°C.