December was a very mild month across the UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland., the fifth warmest in the UK to be exact since 1884, with a mean temperature of 6.2°C, that was +2.0°C above the 1991-2020 LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO.. Rainfall totals were closer to average though, at 110% of the POAPOA Percentage Of Average, the wetter weather in the north balancing out the drier weather across the south. It was a very dull month across the board, sunshine totals were the fourth lowest since 1910, at just 57% of the POA.