Foehn effect gives Scottish village UK's hottest January day

At nearly 20°C, the temperature was 12°C higher than the average maximum for Kinlochewe

A file photo of Kinlochewe. Typically, Scotland is expected to be the coldest place in Britain, yet it has a history of setting January temperature records. Alamy
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A village in northern Scotland has set a provisional UK temperature record for January after reaching 19.6°C on Sunday.

Typically, Scotland is expected to be the coldest place in Britain, yet it has a history of setting January temperature records.

The temperature in Kinlochewe in the north-west, which is pending verification, is more than a degree higher than previous record of villages Inchmarlo and Aboyne in Aberdeenshire, which hit 18.3°C in 2003 while Aber in Ceredigion, Wales, reached the same level in both 1958 and 1971.

It is also 12°C higher than the average maximum temperature for Kinlochewe in January of 7.45°C, according to the Met Office. The average minimum is 1.29°C.

The Foehn effect

Both this potential record and previous January highs in Scotland were due to a weather phenomenon known as the Foehn effect, which causes the warming and drying of air on the side of a mountain facing away from the wind.

The Met Office said the most notable Foehn events tend to occur across the Scottish Highlands where the moist prevailing westerly winds meet high ground near Scotland's west coast.

"You get these really remarkable station temperatures in Scotland where the Foehn effect can come into play as the air interacts with the mountains," spokesman for the Met Office, Oliver Claydon, told The National.

"You wouldn't be able to generate those sorts of temperatures during the winter time through solar energy alone."

The unexpected warmth happens because as the air gets pushed up the mountain on the windward side and gains in altitude, there is a drop in pressure so the air cools, then condenses to form clouds and ultimately rain.

"That takes the moisture out of the air but it also creates energy in the form of heat energy that then gets pushed down the other side of the mountain," Mr Claydon said.

In January 1972 in Montana, a Foehn event resulted in the greatest temperature change over a 24-hour period recorded in the US, rising 57°C, from minus 48 to 9°C.

Sunday's temperature, if confirmed, would also be a record for a winter's day in Scotland.

In a post on X, the Met Office said: “There has provisionally been a new UK January daily max temperature record set today at Kinlochewe where the temperature reached 19.6°C.

“This beats the previous January UK record of 18.3°C set at Inchmarlo and Aboyne in 2003 and Aber in 1958 and 1971.”

As well as potentially setting the record, Kinlochewe was also covered by a yellow weather warning for wind.

The warning was in place for the north-western highlands and Outer Hebrides between 11am and 5pm.

Elsewhere, Scotland's central belt and the eastern coast of Northern Ireland were already under a yellow wind warning, due to last between 10am and 8pm.

A Met Office representative said the temperature in Kinlochewe was the result of a “brisk, mild, southerly flow” combined with a meteorological phenomenon known as “the Foehn effect”.

The representative said: “The Foehn effect takes place when air is forced to rise over the mountain and warms.

“The warming air then travels back down the other side of the mountain, bringing anomalously high temperatures in the area.

“Although it was a mild day, it was also very windy across Scotland.

“Yellow wind warnings are in force, and we have recorded a gust of 71 mph at South Uist in the Western Isles.”

Elsewhere in the Highlands on Sunday afternoon, the Scottish Fire and Rescue Service sent crews to put out a wildfire in the Glencanisp area of Lochinver, which at one point covered about 2.4km.

A representative said: “We mobilised three appliances – two from Ullapool and one from Lairg – and they left the scene at 5pm.”

Updated: January 29, 2024, 2:56 PM