Climate of south-west England
Exceptions include areas to the east of high ground (e.g. Exeter / parts of West Somerset that are subject to a rain shadow effect and annual rainfall is closer to 30 inches).
Cold snaps are generally less intense or prolonged in the south west and rarely does the temperature fall below −15 °C (5 °F).
Similarly, prolonged heat is fairly rare, however in recent years there have been more heatwave related conditions, albeit fairly short affairs but in July 2022 temperatures have hit 36 °C (97 °F) in Bude and other parts of the region temperatures were between 33 and 35 °C (91 and 95 °F) widely in more inland locations.
The south west is the second windiest area of the United Kingdom, the majority of winds coming from the south-west and north-West.
Government organisations predict the area will experience a rise in temperature and become the hottest region in the United Kingdom.
Because of their high altitude they experience lower temperatures and more precipitation than the rest of the south west (approximately twice as much rainfall as lowland areas).
Sunshine is highest on the coast as convective clouds tend to form slightly inland as the ground heats up faster.
This is a smaller area than the UK Government's South West England region, which also covers Gloucestershire, Wiltshire and Dorset.
The sea has less influence towards the north-east of the region, causing January to be the coldest month with mean minimum temperatures from 1 °C (34 °F) or 2 °C (36 °F).
[2] In the months of July and August (the hottest part of the year) daily maxima range from about 19 °C (66 °F) on the coast of Cornwall to 22 °C (72 °F) across inland areas of the north-east (Somerset and North Somerset) and also Exeter due to being situated in the Eastern Lee of Dartmoor.
Inland areas have experienced even colder conditions with −15 °C (5 °F) at Exeter International Airport, Devon in 1958 and at Bastreet, Cornwall in 1979.
Their occurrence is caused by a dry south-easterly air flow off Mainland Europe or the short-lived 'Spanish plume', (caused when low pressure sat to the south west of the UK and High pressure over the Low countries /southern North Sea creates a southerly airflow that sucks up hot air originating from Iberia, and as it crosses Bay of Biscay it picks up moisture and raises humidity levels to uncomfortable levels).
In spring and summer, the sea is cool compared to the air temperature, causing less convective cloud cover.
The convective cloud forms more frequently inland, especially on higher ground such as Dartmoor, Exmoor and Bodmin Moor, thus reducing the amount of sunshine.
In summer, a large proportion of the rainfall is caused by sun heating the ground leading to convection and to showers and thunderstorms.
Highland areas are cooler, causing moist air to cool below the dew point as it rises over high ground forming clouds and then rain.
Instances include the Lynmouth disaster of 15 August 1952, caused by 228 millimetres (9.0 in) of rainfall falling locally on Exmoor over 12 hours.
[4] The north-Cornish village of Boscastle was flooded on 16 August 2004; a peak hourly rainfall of 80 millimetres (3.1 in) was recorded.
[5] From December 2013 onwards the Somerset Levels suffered severe flooding as part of the wider winter storms of 2013–14 in the United Kingdom.
During this period, snow settled, on average, fewer than three days per year across the Isles of Scilly and on the coasts of Devon and Cornwall.
[12] The majority, and the strongest, of the winds are from the south-west and north-east as Atlantic depressions pass from west to east over the United Kingdom.
[12] Islands and exposed headlands have the highest number of days per year of gale-force winds (averaged out over ten consecutive minutes).
Widespread winds from the Burns' Day storm on 25 January 1990 overturned vehicles and damaged buildings.
[12] The Bristol Channel floods on 30 January 1607 apparently caused "many thousand" deaths and may have destroyed several small harbours.
It predicts that the region will have one of the highest annual temperatures in the United Kingdom and there will be an estimated 53 millimetres (2.1 in) increase in winter precipitation.
Following the announcement, the government of the United Kingdom called on the local authorities and other organisation to prepare for the consequences.
Richard Cresswell, the regional director for the Environment Agency in the south west, said: "The latest UK climate change data shows that the risk of flooding and coastal erosion will continue to increase in future due to rising sea levels and more frequent and heavy storms."
£357 million on flood risk management in Cornwall, Devon, Dorset, Somerset, South Gloucestershire and Wiltshire has been spent since 2002, which includes spending continuing into 2009/10.
Since 1990 the drainage board has been charged with looking at the rhynes, cleaning them out and keeping them clear, with the Environment Agency overseeing the work.
