The New Year will be ushered in with some exceptionally mild weather for the UK, before a drop in temperatures to closer to the average early next week.

A low-pressure system to the west of Ireland will draw a plume of warm Atlantic air up from the south west over much of the country, bringing temperatures up into the teens for many places up to and including New Year’s Day.

New Year’s Eve will be mild for most, with temperatures staying in double figures overnight for many. Heavy rain early on New Year’s Eve will largely clear eastwards by New Year’s Day, although rain will linger for some and it will be windy particularly in western areas and over the Pennines.

A mainly dry day for most on Saturday could see temperatures climb above the New Year’s Day record of 15.6°C, set in 1916 in Bude, in Cornwall. Temperatures as high as 15°C could be fairly widespread across the southern half of the UK.

As the low pressure moves north and east going into next week, it will allow colder air from the north to fill in behind it, meaning most places in the UK will see temperatures falling back to nearer average for January, with highs in low double figures in the south, seven or eight °C in the north. Showers, merging occasionally into bands of rain, will move in from the west for all parts, with an increasing likelihood of turning wintry in the north of the UK.

Neil Armstrong, Met Office chief meteorologist, said: “The position of the jet stream and a low-pressure system to the west of Ireland over the next few days mean that a large amount of unusually warm air will be pulled up over the UK.

“While this means a very mild start to the New Year for most in the UK it will soon be replaced by more ‘normal’ January conditions. These warm spells in winter are consistent with what we would expect with climate change, and while cold snaps cannot be ruled out, we would expect above-average temperatures like this to become a more frequent occurrence as the global climate warms.”