Friday
Fairly high pressure over Britain leads to mainly dry conditions. Mostly light winds allowing for some mist and fog to develop, particularly in the west. Otherwise a bright day with plenty of sunshine. Fronts located to the west bring cloud and rain to Ireland, fringing into southwestern England where it is slightly milder. Some showers, possibly wintry, brushing eastern counties of England too. A frosty start leading to a cold day for most. Highs 3 to 8C, mildest toward the southwest.

Friday night
A largely dry night with mist and fog developing again, rather extensively through England and Wales. More cloud across the north and further west with outbreaks of rain and snow on the leading edge through Scotland. Another cold night with frost expected. Lows at 0 to -4C.
 

Saturday
A slack pressure pattern is due to exist with winds remaining light for much of the country. Mist and fog could be slow to clear for some during the day with some patches stubborn to lift at all. Drier and brighter, away from mist and fog, through much of England and Wales. Cloudier skies and patchy rain, snow towards higher ground, across Scotland and Northern Ireland, though milder here in a south-westerly wind flow. Highs 4 to 9C, mildest in west, coolest in central and southeastern areas if it stays murky.

Sunday
High pressure over south and eastern England keeps things mainly dry but still on the cool side here. A risk of fog too. Southwesterly breezes in the north and west bring mild but damp conditions with low cloud, patchy rain and drizzle for Ireland, western Scotland before moving south through Wales and northern England. Highs 4 to 10C.