16th October 2018
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Sunny summer though August unsettled

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Based on the data from Lerwick, this summer in Shetland was more than a degree milder than normal, with a mean temperature of 12.4°C com­pared to the normal 11.1°C. It was – despite a dry June – wet, with rainfall 116.6 per cent of normal, mainly because of a very wet August. Despite this, sunshine was well above average for the three months, with 124.9 per cent. All months were sunny, especially June, with almost twice the normal sunshine.

Across the UK as a whole, the mean temperature for the summer was 14.7°C – 0.6°C above the average. Rainfall was above normal but, as in Shetland, the three months had contrasting patterns, with June drier than normal in most areas. July was much wetter, with over 200 per cent of average rainfall across the country. In August the wettest weather tended to be focused in the north and west.

Sunshine totals for summer were close to average generally across the UK, but were well above average across northern Scotland. June was the sunniest month, with 125 per cent of normal for the UK, and it was particularly sunny over Northern Ireland, northern and western Scotland (150 per cent). Provisionally, it was the second sunniest June over northern Scotland in series that begin in 1929.

Data from the UK Met Office

Initial Statistical details for Scotland as a whole (1961-1990 average) for August:

Mean temperature – 13.5°C (0.7°C above average)

Rainfall – 197.1mm (183 per cent of average)

Sunshine – 133.0 hours (95 per cent of average)

August was unsettled throughout, with showers or longer outbreaks of rain and just a few short drier and sunnier spells. For much of Scotland it was a very wet month, with well above-average rainfall.

Provisionally it equalled 1985 as the wettest August for western Scotland in a series extending back to 1914. While most southern and western areas had less than normal sunshine, the Northern Isles and places closer to the east coast fared better, with about 110 per cent of average. Mean temperatures were 0.5 to 1.0°C above the 1971-2000 normal.

The month began with a depression to the west of Scotland. Rain or drizzle and hill fog, ac­­­companied by a fresh south-easterly wind, spread from the west as fronts moved east over Shetland. Brighter, drier conditions followed for the 2nd as the low filled and pressure built across the area.

The 3rd was dry and sunny, as was much of the next day, although south-easterly winds grad­ually fresh­ened as another depres­sion – deepening to the west – drove fronts across Scotland. These brought rain and mild, misty conditions with extensive hill fog later on the 4th.

As the filling low moved away towards Iceland, winds became light south or south-easterly as an anticyclone developed over Scan­dinavia, and the 5th and 6th were two mainly dry and sunny days with a total of 27.1 hours sunshine for Fair Isle and 24.5 hours for Lerwick.

The 7th, though still dry and bright, was misty at times with coastal and hill fog, as an old front – pushed towards Shetland by building high pressure to the east – added that extra bit of moisture to the light south-easterly winds.

With a shallow area of low pressure to the west, the 8th and 9th were rather cloudy though mainly dry days. A moderate south-easterly breeze brought misty conditions with patchy hill fog, before clearer conditions followed as winds veered south-westerly. Rain arrived early on the 10th, as low pressure tracked east across the north of mainland Scotland and fronts approached the Northern Isles. Freshening winds backed north-easterly in the rain and eventually north-westerly, as bright­er conditions returned to Shetland from the north.

Light south-westerly winds brought mainly cloudy conditions with patchy light rain or drizzle on the 11th and 12th, as a shallow low tracked east to the north of Shetland. As the low moved away and pressure built to the west, north-westerly winds brought a sunny, mainly dry day on the 13th.

A ridge declined east on the 14th, with rain and strengthening south-easterly winds following later in the day, as a deepening depression – swinging in towards north-west Scotland – pushed fronts north-east. Low pressure, lingering close to northern Scotland, brought rain or showers, heavy at times, and oc­casionally misty conditions on the 15th.

As the low moved east and winds freshened north-westerly, the 16th was a rather cloudy and showery day. A much brighter and mainly dry, sunny day followed on the 17th, as the East Greenland high ridged south-east across Iceland towards the UK. Still under the influence of the high, a cool night followed, with a slight grass frost recorded on Fair Isle.

The 18th remained dry though rather cloudy and a little milder, as a weak front pushed up from the south. The high relinquished its hold and – driven east by a large area of low pressure approaching west­ern Scotland – more active fronts brought heavy rain and strong south-westerly wind on the 19th.

During the 20th a small low centre, running north along a front slow-moving near Shetland, brought further periods of occasionally heavy rain and locally strong cy­clonic winds, gusting to over 40mph in Lerwick. Low pressure moved away northwards and brisk south to south-westerly winds brought a brighter day with sunny spells and a few showers on the 21st.

Winds veered south-west to westerly on the 22nd and, while a few places may have seen a shower, many remained dry with lengthy sunny periods. As the next Atlantic low pushed fronts east, winds backed south-easterly and increased fresh to strong on the 23rd, with patchy rain or drizzle spreading from the west.

With a filling depression to the west of Scotland and fronts slow-moving near the Northern Isles, the 24th was rather cloudy with outbreaks of rain dying out. However, as winds fell light it turned rather misty, with fog developing along coasts and over hills.

The 25th was much brighter and mostly dry with sunny spells as the low slipped south, leaving building high pressure in its place. However, the fine weather did not last long, with rain or drizzle accompanied by misty conditions spreading north-east later on the 26th, as winds backed north-easterly, ahead of fronts driven over the Northern Isles by a low.

Outbreaks of heavy rain or showers continued on the 27th and 28th, as the low tracked north-east over the Northern Isles. Strong westerly winds and frequent showers followed on the 29th as the low continued northwards.

The 30th was a brighter and drier day with lighter winds, as the low moved away into the Norwegian Sea and a ridge crossed the area from the west. August ended as it began, with a front – pushed north-east over Shetland by the next Atlantic depression – bringing patchy rain on the 31st.