Climate of Scotland
The climate of Scotland is temperate (Köppen climate classification Cfb), and tends to be very changeable, but rarely extreme. It is warmed by the Gulf Stream from the Atlantic, and given its northerly latitude it is much warmer than areas on similar latitudes, for example Labrador in Canada—where the sea freezes over in winter and icebergs are a common feature in spring and early summer, or Fort McMurray, Canada—where −35 °C (−31 °F) is not uncommon during winter.
Rainfall totals vary widely across Scotland— the western highlands of Scotland is one of the wettest places in Europe with annual rainfall up to 4,577 mm (180.2 in). Due to the mountainous topography of the western Highlands, this type of precipitation is orographic in nature, with the warm, wet air forced to rise on contact with the mountainous coast, where it consequently cools and condenses, forming clouds. In comparison, much of eastern Scotland receives less than 870 mm (34.3 in) annually; lying in the rain shadow of the western uplands. This effect is most pronounced along the coasts of Lothian, Fife, Angus and eastern Aberdeenshire, as well as around the city of Inverness. Inchkeith in the Firth of Forth receives only 550 mm (21.7 in) of precipitation each year, which is the similar to Rabat in Morocco, and less than Sydney or Barcelona receive per year. Also, as a result of this the north-western coast has about 265 days with rain a year and this falls to the south east to a minimum of about 170 days along the coast to the east of high ground. Snowfall is less common in the lowlands, but becomes more common with altitude. Parts of the Highlands have an average of 36" to 105" snow days per year, while some western coastal areas have between 12 and 17 with snow a year.
Scotland has a reputation for cloudiness and this is most notable during its relatively short winter days. The maximum amount of sunshine in a calendar month was 329 hours in Tiree in May 1946 and again in May 1975 while the minimum, a mere 36 minutes, was recorded at Cape Wrath in the Highlands in January 1983. Dundee is the sunniest city in Scotland. On the longest day of the year there is no complete darkness over the northern isles of Scotland. Lerwick, Shetland, has about four hours more daylight at midsummer than London, although this is reversed in midwinter. Annual average sunshine totals vary from as little as 711–1140 hours in the highlands and the north-west, up to 1471–1540 hours on the extreme eastern and south-western coasts. Average annual sunshine hours over the whole territory are 1160 (taking 1971 to 2000 as standard) meaning that the sun shines just over 25% of the time.
Scotland lies in the path of eastward-moving Atlantic depressions and these bring wind and clouds regularly throughout the year. In common with the rest of the United Kingdom, wind prevails from the south-west, bringing warm, wet air from the Atlantic. The windiest areas of Scotland are in the north and west; parts of the Western Isles, Orkney and Shetland have over 30 days with gales per year. Vigorous Atlantic depressions—also known as European windstorms—are a common feature in the autumn and winter in Scotland.
- "Rainfall Amount Annual Average". Met Office. 2001. Retrieved 20 August 2007.
- "Days of Snow Lying Annual Average". Met Office. 2001. Retrieved 20 August 2007.
- "Scotland Sunshine Statistics". Met Office. 2008. Retrieved 7 July 2008.[dead link]
- "Sunshine Duration Annual Average". Met Office. 2001. Retrieved 20 August 2007.
- "Met Office: Scottish climate". Met Office. 2001. Archived from the original on 27 May 2007. Retrieved 20 August 2007.