Met office
UK Outlook for Monday 24 Dec 2018 to Wednesday 2 Jan 2019:
There is low confidence in the forecast as we head into the Christmas period. However, central and western areas are more likely to see cloudy skies and outbreaks of rain on Christmas Eve, whilst it will most likely be drier and brighter elsewhere. Meanwhile, many will most likely see a mild day on Christmas Day itself, with increasing amounts of dry weather. Thereafter, as we continue towards the end of the year, southern parts will probably see a good deal of dry weather, although with this settled weather comes an increased risk of overnight fog and frost. Northern parts, meanwhile, look set to see more changeable weather, with showers or longer spells of rain at times.
UK Outlook for Thursday 3 Jan 2019 to Thursday 17 Jan 2019:
The beginning of this period most likely brings further dry weather in the south but showers and longer spells of rain in the north. However, the unsettled weather may extend to all parts for a time in early January. There is low confidence in the forecast thereafter, although we will most probably see a colder and drier period with the potential for easterly winds and a chance of some wintry weather for parts of the UK. We may also see occasional frontal systems try to make inroads, bringing the chance of further wintry weather in the west. However, despite this potential shift to colder weather, wet, windy and mild weather may still be possible at times.
https://www.metoffice.gov.uk/public/weather/forecast