Climate of Northern Ireland

The climate of Northern Ireland is an oceanic climate, or temperate maritime climate. It is classified as "Cfb" on the Köppen climate classification system. Northern Ireland has a latitude between 54°N and 56°N and winters are much milder and wetter than many other cities on this latitude, such as Moscow, Omsk or Novosibirsk. However, summers are generally cooler and wetter than other cities along a similar latitude. These climatic differences are because of the prevailing westerly winds from the Gulf Stream, a warm Atlantic ocean current. The influence of the Gulf Stream also ensures the coastline of Northern Ireland remains ice-free throughout the winter—unlike for example the Sea of Okhotsk and the Labrador Sea which are at a similar latitude. The climate in Northern Ireland does not experience extreme weather, with tornadoes and similar weather features being rare.cite web|url=http://www.meteogroup.co.uk/uk/home/weather/weather_news/news_archive/archive/2007/september/ch/0c38b61aac/article/tornadoes.html|title=Tornado|accessdate=2008-05-18|publisher="Meteo Group"]

Temperature

Northern Ireland is in the north-west of the United Kingdom and sees milder winters and cooler summers than areas further east and south. The Gulf Stream (specifically the North Atlantic Currentcite web|url=http://www.britannica.com/eb/article-44640/Northern-Ireland|title=Northern Ireland: Climate|accessdate=2008-05-17|publisher="Encyclopædia Britannica"] ) moderates the climate of Northern Ireland, ensuring neither extreme heat in summer, nor extreme cold in winter.cite web|url=http://uk.encarta.msn.com/encyclopedia_761571415/northern_ireland.html|title=Northern Ireland|accessdate=2008-05-17|publisher="Encarta"] The lowest-ever recorded temperature in Northern Ireland was on 1 January 1979, when −17.5°C was recorded at Magherally, near Banbridge, County Down.cite web|url=http://www.metoffice.gov.uk/climate/uk/location/nireland/index.html|title=Met Office:Northern Ireland climate|publisher="Meteorological Office"|accessdate=2008-05-17] In winter, the average maximum temperature is between 6.7°C and 7.5°C, while the average minimum temperature is between 1.2°C and 2.0°C.cite web|url=http://www.metoffice.gov.uk/climate/uk/averages/19712000/areal/n_ireland.html|title=N Ireland 1971-2000 averages|accessdate=2008-05-17|publisher="Meteorological Office"] In summer, the average maximum temperature is between 16.5°C and 18.4°C, while the average minimum temperature is between 8.3°C and 10.6°C. The highest-ever recorded temperature was at Knockarevan, near Belleek, County Fermanagh on 30 June 1976, where 30.8°C was recorded. This record was later equalled at Shaw's Bridge, Belfast on 12 July 1983.

The annual mean temperature for different areas in Northern Ireland also varies. In the mountainous regions, the average mean is under 7°C.cite web|url=http://www.metoffice.gov.uk/climate/uk/averages/19712000/tmean/17.gif|title=Mean Temperature Annual Average 1971-2000|publisher="Meteorological Office"|accessdate=2008-05-18] In most of lowland Northern Ireland the annual average is around 9°C, but around Portrush on the north Antrim coast and Bangor on the north Down coast, the average mean temperature is around 10°C.

Precipitation

Rainfall

Rainfall in Northern Ireland normally comes from Atlantic frontal systems which travel north-east over Northern Ireland, bringing cloud and rain. The west is normally wetter than the east, with up to convert|2000|mm|in in the west, and only convert|825|mm|in around the Lough Neagh basin and the far south-east, including towns such as Kilkeel and Newcastle. Mountainous areas such as the Sperrins, Glens of Antrim and the Mourne Mountains are wetter than the surrounding lowland. Spring is the driest season. October, November, December and January are the wettest months, with each of these months receiving on average over convert|100|mm|in of rainfall. Parts of north-western Northern Ireland receive over 200 days of rainfall over convert|1|mm|in, but in the sheltered south-east, rain occurs under 160 days a year.cite web|url=http://www.metoffice.gov.uk/climate/uk/averages/19712000/dr1/17.gif|title=Days of Rain ≥ 1mm Annual Average 1971-2000|accessdate=2008-05-18|publisher="Meteorological Office"] The highest-ever rainfall recorded in one day was on 31 October 1968 at Tollymore Forest, County Down; convert|158.9|mm|in of rain was recorded on that day.

nowfall

Cold conditions are rare in Northern Ireland with snowfall quite uncommon in the lowlands and on the coast. However, it falls regularly on the hills and mountains in the winter. Snow falls around 10 times a year on the eastern seaboard, while in the mountainous regions it can fall over 30 days a year. Snow does not normally lie on the ground outside of the winter months of December, January and February; the Lough Neagh area, the Bann valley, around Lough Foyle and eastern County Down have fewer than 6 days of lying snow every year.cite web|url=http://www.metoffice.gov.uk/climate/uk/averages/19712000/dl/17.gif|title=Days of Snow Lying Annual Average 1971-2001|accessdate=2008-05-18|publisher="Meteorological Office"] Snowfall is variable, and some winters see no snowfall. The winters of 1962/63 and 1981/82 saw very heavy snowfall. Drifting can occur with strong winds; this can affect busy routes including the Glenshane Passcite web|url=http://news.bbc.co.uk/1/hi/northern_ireland/2723189.stm|title=Schools hit by severe weather|publisher="BBC News"|accessdate=2008-05-17] which is on the A6 road, the main route between the two largest cities in Northern Ireland, Belfast and Derry. The A1 road connecting the capital cities of Northern Ireland and the Republic of Ireland, Belfast and Dublin, has also suffered similar disruption.

Thunderstorms

Thunderstorms are quite rare in Northern Ireland compared to England and Wales, with most places only having on average 3 days of thunder every year. Thunder is most frequent in Northern Ireland in the south-west region, including County Fermanagh and parts of western County Tyrone. However, thunder still usually occurs in this area fewer than 6 times a year.cite web|url=http://www.metoffice.gov.uk/climate/uk/averages/19712000/dt/17.gif|title=Days of Thunder annual average 1971-2000|publisher="Meteorological Office"|accessdate=2008-05-18]

unshine

The east of Northern Ireland, which is sheltered from Atlantic frontal systems, is sunnier than the west. The sunniest region, the Ards Peninsula, receives up to 1,500 hours of sunshine every year. Further west, the hours of sunshine decreases, and the forested mountainous north-west receives on average under 1,100 hours of sunshine.cite web|url=http://www.metoffice.gov.uk/climate/uk/averages/19712000/ss/17.gif|title=Sunshine Duration (hours) Annual Average 1971-2000|publisher="Meteorological Office"|accessdate=2008-05-18] The average recording of sunshine for the whole country is 1219.7 hours. December is the dullest month with 31.8 hours sunshine, which equates to just over one hour per day. May is the sunniest month and receives 175.9 hours of sunshine—this is because of its long days and fine weather.

Wind

Northern Ireland lies in the path of low pressure systems moving north-east across the United Kingdom from the Atlantic. As well as rain, these frontal system can bring strong winds. Gales are not as common in Northern Ireland, as they are in the more exposed Hebrides in Scotland, or the far south-west of England. Gales occur around 15 days a year on the Antrim and Down coast, but occur inland on average fewer than 5 times a year. In the hills and mountains, wind speed is higher than in the lowlands. The east coast sometimes experiences cold winds in the winter, which come from the Siberian High.

Frost

Air frost occurs frequently in the winter, with most areas seeing over 40 days of air frost every year. Air frost occurs on average 10.2 days every January, the month in which air frost occurs most frequently. Along the coast, air frost occurs less regularly. In the Sperrins and the Glens of Antrim air frost occurs around 80 days of year.cite web|url=http://www.metoffice.gov.uk/climate/uk/averages/19712000/daf/17.gif|title=Days of Air Frost 1971-2000|publisher="Meteorological Office"|accessdate=2008-05-18] The pattern is similar with ground frost, with on average around 100 days of ground frost in the lowlands and over 140 in the mountains.cite web|url=http://www.metoffice.gov.uk/climate/uk/averages/19712000/dgf/17.gif|title=Days of Ground Frost 1971-2000|publisher="Meteorological Office"|accessdate=2008-05-18]

Visibility

Visibility is generally very good, because of the proximity of industry to the coast, allowing breezes to disperse any smoke. Mist and fog and often occur, as well as coastal fog in the east, but it is generally not long-lasting. However in winter, it can be slow to clear.

ee also

*Climate of the United Kingdom
*Climate of Ireland

References