Many parts of the US witnessed the warmest Christmas Day on record. Temperatures rose above 15-30 degrees Celsius higher than the seasonal average.
In multiple areas, weather conditions prevailed like those of April or May.
On Christmas Eve, on Tuesday, Oklahoma City recorded 25 degrees Celsius, only to surpass the previous record of 22 degrees Celsius that prevailed in 1982.
"Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina, recorded temperatures above 25 degrees Celsius," the Guardian reported.
Above-average warmer conditions are expected to prevail in the coming days as unseasonal heat is forecast to sweep into the south-eastern States later this week.
The warmer days were triggered by a strong upper-level ridge extending from the desert south-west towards the north and east, creating a heat-dome effect.
A heat dome effect is a weather phenomenon where a high-pressure system traps hot air over an area for days or weeks, like a lid on a pot. The trapped air gets compressed and reheated by the sun, leading to a stark increase in temperature.