Northern Ireland Climate – September 2026 Update

Post-WWII industrial expansion begins

After the Second World War, coal and oil use grew rapidly across Europe, North America and the Soviet Union. Global sulphur dioxide emissions rose from about 30 to about 130 million tonnes a year by 1980, and the sulphate haze they formed masked part of the greenhouse warming underneath - the effect known as 'global dimming'.

Klimont et al. 2013

The North Sea Flood of 1953

The Stranraer-Larne ferry Princess Victoria sinks in the North Channel about five miles north-north-east of the Copeland Islands on 31 January 1953, five miles short of Northern Ireland. 135 people die and 44 survive, all of them men - the deadliest maritime disaster in UK waters since the Second World War, and the single worst incident of a storm that killed 531 people across the UK.

The Conversation, Royal Meteorological Society, Wikipedia, Wikipedia (2)

UK Clean Air Act

The Clean Air Act 1956 did NOT extend to Northern Ireland - apart from a single section, it applied only to England, Wales and Scotland. The Parliament of Northern Ireland legislated separately eight years later, in the Clean Air Act (Northern Ireland) 1964, so smoke control arrived here later than in the rest of the UK.

The National Archives, Clean Air Act 1956, The Clean Air Act 1964 (Appointed Day)…

The Big Freeze of 1962-63

Northern Ireland shared in the UK's coldest winter since at least 1895, but January 1963 is not its own coldest month - in Northern Ireland's monthly series back to 1900 it ranks 3rd, at -0.2°C, behind December 2010 (-0.7°C) and February 1947 (-0.5°C). The Big Freeze is a Central England superlative more than a Northern Irish one.

Wikipedia, Wikipedia (2), Royal Meteorological Society, Norfolk Live

Agung eruption

Agung's eruption in Bali put a veil of sulphate haze into the stratosphere that cooled global temperature by about 0.3°C over 1963-66.

Smithsonian Global Volcanism Program, NOAA Global Monitoring Laboratory

The 1976 UK drought

Northern Ireland faced a curtailment of water supplies for around 12 hours a day as reservoirs rapidly depleted during the same drought, with domestic users last in line behind industry and agriculture.

The Irish News

Global SO2 emissions peak

Global sulphur dioxide emissions peak at about 130 million tonnes a year, then begin a long decline as Europe, North America and Japan clean up their air. As the aerosol mask thins, the rate of global warming picks up through the 1980s.

Klimont et al. 2013

El Chichón eruption

A sulphur-rich eruption in Mexico whose aerosol cloud stayed in the stratosphere for more than two years, cooling the Northern Hemisphere by about 0.2°C.

Smithsonian Global Volcanism Program

Daytime warming catches up with the night-led pattern

Across 1961-90, 81% of the world's land saw nights warming faster than days. Across 1991-2020 the pattern reversed: 70% saw days warming faster, as the industrial haze that had been dimming daytime sunshine was cleaned up. The study compares two fixed thirty-year windows; measured as a turning point, this site's own global series turns around 1982.

Zhong et al. 2023

The Burns' Day Storm

An intense depression crosses southern Scotland on 25 January 1990, driving severe gales across England and Wales in broad daylight. 47 people are killed - more than twice the toll of the Great Storm of 1987 - around 3 million trees come down and 500,000 people lose power. Damage was heaviest south of a line from west Wales to Suffolk.

Met Office, Royal Meteorological Society

August 1990 UK heatwave breaks 79-year record

Northern Ireland saw far milder conditions during the same spell - its own record, 30.8°C set at Knockarevan in 1976, stood untouched and wasn't broken until 2021.

Wikipedia

Positive NAO phase dominates the 1990s

Northern Ireland lies in the part of the UK where the NAO's rainfall signature is most consistent - the north-west - so the strongly positive phase of the 1990s shows up here as a clearer wet-and-mild winter signal than it does in southern or eastern England.

Hurrell 1995, Science, Atmosphere, 2021, Frontiers, 2022NAO Tracker

Atlantic Multidecadal Oscillation flips to a warm phase

The Atlantic Multidecadal Oscillation flipped to a warm phase in 1995. For the UK it is one of the background rhythms sitting underneath the warming trend: warm AMO phases are associated with warmer North Atlantic surface waters on the UK's doorstep, and have been linked to wetter summers in parts of north-west Europe. It is a natural cycle of roughly 60-70 years, so it shifts the baseline rather than driving the long-term trend - which matters when reading any UK record set since the mid-1990s.

Learn more →

August 2003 European heatwave (UK)

Northern Ireland's high of the August 2003 heatwave was 29.3°C at Castlederg, Co Tyrone, on the 8th - warm, but comfortably short of the 30.8°C national record that had stood since 1976 and was not beaten until July 2021, when Castlederg itself reached 31.3°C. The 2003 heat was an English and continental event; Northern Ireland sat on its cool north-western edge.

News Letter

Summer 2007 UK floods

Northern Ireland records its wettest June on the instrumental record in 2007 - 154.5mm, beating the 147mm of June 1931 - and is among the first areas hit when the summer's flooding begins on 14 June. East Belfast and Omagh take around 50mm of rain in two to four hours on 12 June, overwhelming drains and watercourses.

Wikipedia / GOV.UK flood cost report, Met Office

Negative NAO blocking cluster, 2009-2013

December 2010 is the coldest single month in Northern Ireland's record, averaging -0.7°C against a series running back to 1900 - colder than February 1947 and than any month of the 1962-63 Big Freeze. On the 23rd Castlederg in County Tyrone fell to -18.7°C, the lowest temperature ever recorded in Northern Ireland. The cause was a blocked negative-NAO pattern, with high pressure over Greenland steering Arctic air south.

4byo, Met Office, WikipediaNAO Tracker

Start of the sustained rise in UK heatwave frequency

Northern Ireland's own Heatwave Days count rose from a decade mean of 1.93 days in the 2000s to 5.59 in the 2010s, and 12.52 so far in the 2020s - the same sustained UK-wide acceleration.

Met Office, State of the UK Climate

UK's post-2013 warmth acceleration

6 of Northern Ireland's own 10 warmest years on record have occurred since 2013.

Met Office, State of the UK Climate

2015-2025: the eleven warmest years on record

Globally, the eleven warmest years on record have all happened since 2015. Northern Ireland's own record is a looser fit - five of its eleven warmest fall in that span, with 2014, 2007, 2006, 2005, 1997 and 1949 outside it. Its warmest year is 2023.

Learn more →

North-west flash flooding, August 2017

Around 63% of an average August's rain falls on north-west Northern Ireland in eight or nine hours on 22 August 2017. Derry is left virtually inaccessible by road and its airport closes; across the border at Malin Head, 77.2mm makes it the wettest August day there since 1955.

Department for Infrastructure NI, University College Cork

The Beast from the East

The same cold snap triggers a Met Office amber warning for Northern Ireland and closes hundreds of schools there, though a comparable regional snow-depth figure is not clearly documented. It followed a sudden stratospheric warming in mid-February that split the polar vortex.

Q RadioPolar Vortex Tracker

Low-sulphur shipping fuel rule (IMO 2020)

New international shipping rules cut the sulphur allowed in ship fuel from 3.5% to 0.5% almost overnight, removing about 8 million tonnes of sulphur dioxide a year. With less sulphate haze over the oceans, it may have added around 0.1°C of warming by 2023-24.

Gettelman et al. 2024

The UK's wettest February on record, 2020

February 2020 was Northern Ireland's wettest February in this site's Met Office record from 1900 - 231.8mm, nearly three times its 1961-90 average - as Storms Ciara, Dennis and Jorge followed one another in on a strong, southward-shifted jet stream. It beat the 194.9mm of February 1990.

Davies et al. (2021), Carbon Brief / Met Office, NOAA CPCPolar Vortex / AO

The UK's first 40°C day

Northern Ireland reached 31.2°C at Derrylin, County Fermanagh, during the July 2022 heat - within 0.1°C of its national record, which had been set only the year before in 2021 and was not broken. England passed 40°C for the first time on the 19th.

Met Office review (via Carbon Brief), Met Office, Wikipedia, Met Office (2)

Northern Ireland's wettest July on record

185.4mm of rain (207% of the long-term average) - narrowly beating the previous record of 185.2mm set in July 1936, in a series dating back to 1836.

Met Office

Storm Éowyn

Storm Éowyn sets the highest wind gust ever recorded on the island of Ireland on 24 January 2025 - 114mph at Mace Head, County Galway - with gusts over 90mph in Northern Ireland. Around 100,000 Northern Irish properties lose power, alongside 725,000 in the Republic.

Wikipedia, Met Office, Met Office (2)