The south-west is the second most exposed area of the United Kingdom; second to western Scotland. The strong winds are caused by deep depressions across or close to the British Isles. Winds are stronger in the winter-half year, as the depressions' strength and frequency increase. The lightest mean wind speeds are in summer. The speed of peak gusts and mean wind speed follow a similar pattern throughout the year.
Mean wind speeds are generally lower to the north-east of the region and in inland areas. Yeovilton, lowland Somerset, has a mean wind speed that is two thirds that of St. Mawgan in coastal Cornwall. An increase in altitude in inland areas generally increases the mean wind speed; similar wind speeds are recorded on the highest parts of Exmoor and Dartmoor as on the coast.
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. When an Atlantic depression reaches the United Kingdom, winds usually blow from the south or south-west, and they change to west or north-west when the depression leaves. If a depression passes along the English Channel, strong winds can occur from the east or north-east. Due to anticyclogenesis over Scandinavia, the majority of winds in Spring are from the north-east. Coastal areas of the south-west usually experience calm or very light winds that do not have a classifiable wind direction less than 6% of the time; this figure is 15% in the north-east and inland areas.
Carland Cross Wind Farm, Cornwall
Islands and exposed headlands have the highest number of days per year of gale-force winds (averaged out over ten consecutive minutes). A gale-force wind is defined as being at least 34 knots (63 km/h; 39 mph), which is 8 on the modern Beaufort scale. Gales are recorded approximately 24 days per year in the Isles of Scilly and coastal Cornwall. Further north-east and further inland, the number of days decreases. Plymouth, coastal Devon, receives 16 days; Yeovilton, Somerset, receives seven; and Long Ashton, north-west Somerset, receives four. Wind speeds can vary on local topography: wooded or urban areas sheltered by hills receive fewer days of gales and lower wind speeds.
On 15 December 1979, there were gusts of 91 knots (169 km/h; 105 mph) at Lizard Point, Cornwall 99 knots (183 km/h; 114 mph) at St Mary's, Isles of Scilly and 103 knots (191 km/h; 119 mph) at Gwennap Head, Cornwall. Widespread winds from the Burns' Day storm on 25 January 1990 overturned vehicles and damaged buildings. It caused the highest wind speed during the 1971–2001 period to be recorded in two stations: 84 knots (156 km/h; 97 mph) at Plymouth and 85 knots (157 km/h; 98 mph) at St Mawgan. 79 knots (146 km/h; 91 mph) was recorded on top of a building in Bristol as well as 74 knots (137 km/h; 85 mph) at Exeter International Airport and 68 knots (126 km/h; 78 mph) at Yeovilton. At Plymouth, the maximum hourly mean speed was 60 knots (110 km/h; 69 mph) and at Yeovilton, 45 knots (83 km/h; 52 mph).[12] The Bristol Channel floods on 30 January 1607 apparently caused "many thousand" deaths and may have destroyed several small harbours. The cause of it is disputed to be either a European windstorm or a tsunami.
https://en.wikipedia.org/wiki/Climat...t_England#Wind
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