Met office
UK Outlook for Monday 19 Mar 2018 to Wednesday 28 Mar 2018:
Monday will be another very cold day, it will also be largely dry and bright aside from a few snow showers. Gradually, from Tuesday onwards, wet, windy and milder weather is expected to make a return, particularly in the north where rain is likely to be preceded by a spell of snow. In the south it should remain dry, bright and cold with some sunshine. However, later in the week, wet and windy weather is likely to push across all parts before we see a return to colder and brighter weather by the weekend. Into the following week there is significant uncertainty in the forecast but a blocked or only slowly changing weather pattern seems most likely.
UK Outlook for Thursday 29 Mar 2018 to Thursday 12 Apr 2018:
There is significant uncertainty in the forecast throughout this period, but a blocked or slowly changing weather pattern is probable. There will most likely be a balance between Atlantic frontal systems affecting the south and west at times with colder air associated with high pressure out to the northeast. Mixed conditions are likely with wetter than average conditions expected across the south, while staying drier and perhaps colder to the north. Further snow is possible, especially in the north where it will also be windy at times. Temperatures will likely be below average with further night frosts, and any milder interludes will probably be only brief.
https://www.metoffice.gov.uk/public/weather/forecast