Highlands & Islands

UK's new warmest December confirmed in Highlands

Achfary Image copyright Geograph/Roger Davies
Image caption A temperature of 18.7C was recorded in Achfary on 28 December

A new maximum temperature for December in the UK has been confirmed.

Data suggested a temperature of 18.7C was reached at Achfary, in the Scottish Highlands, on 28 December.

The Met Office has now verified it was the hottest day of the month on record in Britain.

The previous record was 18.3C, in Achnashellach in the Highlands on 2 December 1948. The temperature has been put down to a meteorological phenomenon known as the Foehn Effect.

This is a change from wet and cold conditions on one side of a mountain to warmer and drier conditions on the other side.

The most notable Foehn events tend to occur across the Highlands, where moist prevailing westerly winds encounter high ground along Scotland's west coast.

Record-breaking month

It was the second time a Highlands temperature record was broken in December.

A record temperature of 16.8C was verified for Cassley in Sutherland.

It was recorded at 03:00 GMT on Sunday 29 December. It is the highest on record for 29, 30 or 31 December.

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Media captionWhat are the Foehn winds are and how can they influence our weather?

What is the Foehn Effect?

It occurs when moisture-laden, high humidity air is pushed over high ground by strong winds. As it rises, the air cools and condenses, forming cloud and rain.

Dry air then travels down the other side of the mountain, picking up heat as it goes and resulting in higher temperatures at ground level.

In the UK, this effect is commonly seen in eastern Scotland, north-east Wales and north-east England.

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