Sunshine and increasingly frequent and heavy showers.
There will be a lot of sunshine at first but as the day goes on, Wales will become increasingly cloudy and breezy. Showers will gradually spread inland from coastal areas, becoming heavy, blustery and perhaps thundery by afternoon. Maximum Temperature 10C.
Blustery, heavy and sometimes thundery showers will continue during the first part of the night but ease before morning. Any frost or fog will be confined to the mountain tops. Minimum Temperature 5C.
Longer sunny spells are likely on Thursday but a brisk breeze will develop. A few showers are likely here and there, mainly in the afternoon. Maximum Temperature 10C.
Outlook for Friday to Sunday:
Heavy rain and strong winds early on Friday morning will soon clear to leave brighter mainly dry weather for Friday and Saturday. However, more rain is likely on Sunday.
Day 6 to 15
Sunday will see a band of cloud and rain move northeastwards, followed by a mixture of sunny spells and further organised bands of rain or heavy showers. It'll be windy too, especially towards the coasts in the south and west. Temperatures will tend to stay mild for the time of year. The north and west is likely to stay rather wet and windy on Christmas Eve, with the rest of the UK looking drier. For Christmas Day itself, it may be drier, brighter and colder for most, followed by some rain later. As we head towards the New Year, dry cold and bright weather becomes more likely, with any weather systems becoming increasingly confined to the north or northeast.
Day 16 to 30
Through the first half of January, there is an increasing likelihood that colder weather may begin to dominate with a greater chance of seeing east or northeasterly winds. Should this occur, then wintry conditions are possible in eastern, southern and central areas with western parts of the UK staying relatively drier. Though should any Atlantic frontal systems try to make inroads western areas could also see some snow. Although signals suggest that a cold spell is the most likely scenario in early January, the extent and longevity of the cold weather is uncertain. Wet, windy and mild weather may still be possible at times.
Met Office : WL : 2018-12-19T00:44:50