“To adopt a Stevensonian phrase, the climate of Orkney is one of the vilest under heaven.”
Orkney’s temperate, but wet, climate is heavily influenced by the sea, in particular the Gulf Stream — a warm, surface ocean current from the Gulf of Mexico.
The Gulf Stream flows north-east across the Atlantic Ocean and brings with it the humid air that makes Orkney’s climate much milder than other areas on the same latitude.
Thanks to the Gulf Stream, there is less than 10 deg C difference between the average summer and winter temperatures.
We experience milder winters (average temp 5/6 degrees C) but lower summer temperatures (average 15 degree C with a maximum of around 19 deg C).
“[Orkney’s] one outstanding characteristic is wind. No other region in Great Britain can compare with it for the violence and frequency of its winds”
To the visitor to Orkney, the wind is perhaps the most commented aspect of the islands’ weather. Even in the summer there is an almost constant breeze (usually a Force three or four on average) and this can give a biting edge to the warmest of days.
Strong winds are common, carrying with them salt from the sea, which in turn affects vegetation. In winter, gales are common with an average of 52 hours of gales recorded annually.
In the dark half of the year, the average wind speed increases to around Force 6, often force 7 or 8. More extreme gales, where the windspeeds are over 90 mph, occur relatively frequently, although usually only in short bursts. The worst of these gales was recorded in 1953 – an event that saw considerable damage through the isles.
Because of the Gulf Stream, winter temperatures rarely dip below freezing, so snow is uncommon – usually restricted to a few days at a time.
Recent years, however, have seen some heavy falls relating to Arctic winds from the north.
In these cases, although the quantity of snow is small compared with other regions, the effect of the ever present wind, and subsequent drifting, is generally what causes the greatest problems.
“This cold uncongenial weather sometimes continues till the month of June is considerably advanced.”
Although we see little snow, an Orkney winter is generally very wet – a combination of the low level of the land and the warming effect of the surrounding sea.
Fog and mist
Fog and sea-haar are perhaps the most frustrating aspect of Orkney’s weather.
Haar – a damp fog from the sea – is common all year round, buy generally more so in the warmer summer months when there is a lack of wind to clear the air. At this time, until recent years, Orkney was left isolated as air traffic, in and out of the islands, ground to a halt.
“In the terrible gales that usually occur throughout the year, all distinction between air and water is lost; the nearest objects are obscured by veils of stinging spray and it seems for a while that a cloak of thick grey smoke has settled over the islands.”
The eastern coasts are more prone to fog than the west – in these cases it is possible for the West Mainland to be basking in sunshine while the East is blanketed in a thick grey blanket of fog.