<P> The whole of Northern Ireland has a temperate maritime climate, rather wetter in the west than the east, although cloud cover is persistent across the region . The weather is unpredictable at all times of the year, and although the seasons are distinct, they are considerably less pronounced than in interior Europe or the eastern seaboard of North America . Average daytime maximums in Belfast are 6.5 ° C (43.7 ° F) in January and 17.5 ° C (63.5 ° F) in July . The highest maximum temperature recorded was 30.8 ° C (87.4 ° F) at Knockarevan, near Garrison, County Fermanagh on 30 June 1976 and at Belfast on 12 July 1983 . The lowest minimum temperature recorded was − 18.7 ° C (− 1.7 ° F) at Castlederg, County Tyrone on 23 December 2010 . </P> <P> Northern Ireland consists of six historic counties: County Antrim, County Armagh, County Down, County Fermanagh, County Londonderry, County Tyrone . </P> <P> These counties are no longer used for local government purposes; instead there are eleven districts of Northern Ireland which have different geographical extents . These were created in 2015, replacing the twenty - six districts which previously existed . </P> <P> Although counties are no longer used for local governmental purposes, they remain a popular means of describing where places are . They are officially used while applying for an Irish passport, which requires one to state one's county of birth . The name of that county then appears in both Irish and English on the passport's information page, as opposed to the town or city of birth on the United Kingdom passport . The Gaelic Athletic Association still uses the counties as its primary means of organisation and fields representative teams of each GAA county . The original system of car registration numbers largely based on counties still remains in use . In 2000, the telephone numbering system was restructured into an 8 digit scheme with (except for Belfast) the first digit approximately reflecting the county . </P>

When did n ireland become part of the uk