England SW & South Wales Climate – Sep 2026September 2026 Update

The Bristol Channel flood of 1607

Britain's deadliest recorded flood drowns both shores of the Bristol Channel on 30 January 1607, killing an estimated 500-2,000 people and inundating about 200 square miles of farmland up to 14 miles inland - the Somerset Levels in England and the Gwent Levels in south Wales alike.

Wikipedia, Phys.org

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 Lynmouth flood disaster

On the night of 15-16 August 1952, around 90 million tons of rain falls on an already saturated Exmoor. The East and West Lyn rivers tear through Lynmouth in north Devon carrying boulders and debris, destroying over 100 buildings and killing 34 people.

Wikipedia, Visit Lynton & Lynmouth

The UK's wettest day on record

Severe thunderstorms over southern England on 18 July 1955 drop 279.4mm of rain on Martinstown in Dorset in a single day - still the highest daily rainfall ever recorded anywhere in the United Kingdom.

Met Office Archive, Wikipedia

UK Clean Air Act

The first major clean-air legislation in Great Britain, passed after London's Great Smog of December 1952 killed around 12,000 people. It created smoke control areas and cut domestic coal burning, beginning the long decline in UK and European aerosol emissions. It did not extend to Northern Ireland.

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

The Big Freeze of 1962-63

The blizzard of 29-30 December 1962 hit this region on both sides of the border at once, driving snowdrifts up to 6 metres deep across Wales and south-west England and opening the coldest winter since at least 1895 in every UK meteorological district.

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

Parts of south-west England went 45 days without a drop of rain in summer 1976, while across the border in south-east Wales the Brecon reservoirs dried up completely and mains water was switched off for up to 17 hours a day.

Royal Meteorological Society, Met Office, Royal Meteorological Society (2)

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

The 1981 tornado outbreak

On 23 November 1981, 104 confirmed tornadoes touch down across England and Wales in a single day - the largest tornado outbreak ever recorded in Europe. The worst damage is in Leicester, where hundreds of homes are hit and 24 people are injured as part of a school collapses.

Wikipedia, Wikipedia (2)

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

Gwennap Head in Cornwall shared the storm's highest gust of 107mph on 25 January 1990, and the coast from Cornwall eastwards saw gusts over 92mph. This region lay squarely inside the worst-hit band, south of a line from west Wales to Suffolk.

Met Office, Royal Meteorological Society

August 1990 UK heatwave breaks 79-year record

Cheltenham, in this region, records 37.1°C on 3 August 1990 - a new UK national temperature record, and the first time the 36.7°C of August 1911 had been beaten in 79 years.

Wikipedia, history.co.uk, Met Office

Positive NAO phase dominates the 1990s

South-west England and south Wales sit on the windward side of a positive NAO, with Atlantic moisture lifting over Dartmoor, Exmoor and the Brecon Beacons. The wet signal here is clearer than further east, where the uplands provide shelter.

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 →

The autumn 2000 floods

2000 is this region's wettest year on record at 1,619mm, during the wettest autumn England and Wales had seen since the rainfall series began in 1766.

Unda, Met Office

August 2003 European heatwave (UK)

2003 was this region's 7th-driest year in 126 years of regional record - 959 mm - alongside its 13th-warmest by daily maximum. The heatwave's headline reading, the UK's first 38.5°C, was taken at Brogdale in Kent, at the far eastern end of southern England; what the south-west and south Wales got was the drought that came with it.

Met Office / ONS, Impact of the 2003 heat wave on daily…

The Boscastle flash flood

About 185mm of rain falls on the hills above Boscastle in Cornwall on 16 August 2004 - some 75mm of it in two hours, a whole August's worth. River levels rise two metres in an hour and tear through the village. No one is killed, but the flood becomes Britain's textbook flash-flood case study.

Wikipedia, RMetS MetLink

Summer 2007 UK floods

The final and most damaging episode of the 2007 floods, on 28 July, struck this region on both sides of the border at once - Gloucestershire, Herefordshire and Worcestershire alongside South Wales. Over 350,000 people in Gloucestershire were left without clean drinking water for days after Mythe treatment works flooded.

Wikipedia / GOV.UK flood cost report, Met Office

Negative NAO blocking cluster, 2009-2013

December 2010 was the UK's coldest December since Met Office records began, at a national mean of -1°C - notable this far south west, where the Atlantic usually keeps winters mild. The blocking pattern shut that influence off for weeks.

4byo, Met Office, WikipediaNAO Tracker

Start of the sustained rise in UK heatwave frequency

This region has the steepest rise anywhere in England and Wales - a decade mean of 3.74 Heatwave Days in the 2000s, 9.08 in the 2010s, and 17.83 so far in the 2020s, nearly five times the 2000s figure.

Met Office, State of the UK Climate

UK's post-2013 warmth acceleration

6 of this region's 10 warmest years on record have occurred since 2013, with 2023 the warmest - a slightly less concentrated version of the post-2013 acceleration seen elsewhere in the UK.

Met Office, State of the UK Climate

Somerset Levels floods, winter 2013-14

The Somerset Levels, in this region, took the worst of the winter of 2013-14 - about 100 million m³ of floodwater covering 65 km², the largest flood on record there, with some communities cut off for weeks. Devon, Dorset and Cornwall were also badly hit.

Met Office

The 2013-14 winter coastal storms

A relentless run of Atlantic storms batters the south-west coast through the winter of 2013-14. Waves overtop defences across Cornwall, Devon and Dorset, over 7,000 homes and businesses flood, and on 4-5 February the sea tears away the main railway line at Dawlish, cutting Cornwall and much of Devon off by rail for two months.

Met Office, Earth Surface Processes and Landforms

England and Wales' wettest winter since 1766

Winter 2013-14 (December to February) brought this region 691mm of rain, 186% of the 1961-90 average - its wettest winter since this site's Met Office regional record begins in 1901. Across England and Wales as a whole it was the wettest winter since the series began in 1766.

Met Office, Kendon et al. 2015, England and Wales Precipitation series

2015-2025: the eleven warmest years on record

Globally, the eleven warmest years on record have all happened since 2015. England SW & South Wales's own record is a looser fit - six of its eleven warmest fall in that span, with 2014, 2011, 2007, 2006 and 1921 outside it. Its warmest year is 2023.

Learn more →

The Beast from the East

The deepest snow of the whole Beast from the East fell in this region: 57cm in Gloucestershire, as Storm Emma ran into the Siberian air from the south-west on 1-2 March 2018. The south-west and south Wales, which usually escape the worst of a UK cold snap, took the heaviest widespread fall in the country. It followed a sudden stratospheric warming in mid-February that split the polar vortex.

Wikipedia, Wikipedia (2)Polar 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

February 2020 floods (Storms Ciara & Dennis)

South Wales, in this region, took the worst of Storm Dennis in February 2020 - the River Taff at Pontypridd reached its highest level since records began in 1968 and the Usk broke its 1994 record, with 3,130 properties affected across Wales.

Natural Resources Wales

The UK's wettest February on record, 2020

February 2020 brought this region 240.9mm of rain, two and a half times its 1961-90 average - its second-wettest February in this site's Met Office record from 1900, behind 1923's 248.0mm - as Storms Ciara, Dennis and Jorge followed one another in on a strong, southward-shifted jet stream. Storm Dennis brought severe flooding to south Wales.

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

The UK's first 40°C day

2022 is this region's warmest year by daily maximum in 126 years of regional record - the warmest of any year, anywhere in its series - and its 5th-highest for heatwave days. The UK's first 40°C reading came at Coningsby in Lincolnshire, on the other side of the country, but the year as a whole was more exceptional here than the single reading suggests.

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