Achnagart DCNN0448 – Foehn Effects and Winter Records.

57.18142 -5.37460 Met Office CIMO Assessed Class 5 Temperature records from 1/4/2003

Achnagart Farm is a remote location in north west Scotland close to the A87 (Old Military Road) on the way to Kyle of Lochalsh. Lying close to the valley floor of the River Shiel at just 15 metres amsl it is surrounded by peaks over 1,000 metres amsl. The coast at Invershiel on the sea Loch Duich is under 4 miles away. This might not seem a location likely to record UK wide highest temperatures but, at times of the year, it regularly does due to the Foehn Effect.

During January 2025 , the UK’s highest daily temperatures were often recorded in north west Scotland – once at Aultbea, twice each at Achnagart and Cassley , and three times at Achfary. These statistics might lead some to conclude this is a good area to visit for winter warmth but that most certainly would not be the case. Although this area (and particularly the Western Isles) may have infrequent frosts on the coastal low lying fringes, they are by no means generally warm. The topography of the area leads to occasional weather effects which can cause sudden and dramatic increases in temperature known as the Foehn Effect. This effect is well known and documented by the Met Office themselves.

So what the Met office is noting in its “Climate Extremes” is not the general climate of an area but rather the occasional rare incidence of known weather effects not climate. Three of the twelve UK national all time highs recorded as “Climate Extremes” are in fact Foehn Effects noted at either Trawsgoed (Wales also experiences Foehns) or Achfary.

The Met Office, however, often seems not to read its own web pages notably those on the difference between weather and climate and comes to some quite remarkable conclusions that the Talkshop has highlighted in the past. I strongly recommend reading Roger’s article and all the associated discussion comments about this perverse Met Office representation of the Foehn Effect on the flatlands of East Anglia.

During a recent conversation with a former independent weather forecaster (1970s to 1990s era) I was told that such “freak” weather events were routinely disregarded by the Met office in the past but that now they regularly “chase them” for dramatic effect. He added their inclusion in climate reconstructions is typical of data “gerrymandering”. Checking the installation dates of many of these Foehn Effect sites reveals the likes of Achnagart recording temperature from just 1/4/2003 and Achfary from 1/10/2006. Most damning though is that both sites are CIMO ranked “Class 5 (additional estimated uncertainty added by siting up to 5 °C)”

Looking at the Achnagart site in detail reveals a travesty of a weather station. If data from a private weather station that was as poorly sited as this were offered to the Met Office they would instantly reject it as grossly unsuitable. However, as it is one of their own, everything it produces is treated as “excellent” quality. Below is the current aerial close up image from 2021.

The screen enjoys its own cosy tree-lined enclosure to the north and east with shading effects evident from the west round to south – a classic Class 5 site unworthy of a national tax payer funded meteorological authority…….but at least it is not quite as bad as Achfary.

In summary the Met Office is clearly seen to be manipulating historical climate data by the unwarranted inclusion of unrepresentative weather “extremes” such as at Achnagart and others to its modern climate record. It is hardly surprising to see 21st century significant uplifts when it is shown such previously ignored extremes are now not only included but actively sought out.