An anticyclonic spell ended as October began, with several depressions – separated by transient ridges – tracking east close to Shetland between the 3rd and 12th. Anticyclonic conditions returned to the UK during a 10-day period mid-month. However, on its northern flank Shetland lay in a mild and unsettled south-west to westerly airflow. A brief cyclonic period followed, as a deep depression tracked east over mainland Scotland. The last five days of the month were again more anticyclonic. This time – squeezed between high pressure to the east and low over the Atlantic – a strong southerly airflow affected Shetland.
With an anticyclone to the west of the British Isles the 1st was a bright day, with a few showers dying out by evening as fresh north-westerly winds fell light, leading to a cool night with a local grass frost. Southerly winds steadily strengthened on the 2nd as high pressure sank south, with a front bringing heavy overnight rain to Shetland. This cleared early on the 3rd and, as a depression tracked east over Shetland, winds fell light and variable for a time before strengthening north-westerly winds brought squally showers across the Isles later. A mixture of sunny spells and scattered showers followed on the 4th, as the low moved away and winds eased.
The 5th started cool and bright with a widespread grass frost. As an Atlantic low – tracking east towards Scotland – pushed fronts north-east over the Northern Isles, south-easterly winds freshened and rain followed later in the day. The low moved east to the north of Shetland on the 6th and rain cleared to sunshine and showers, as strong south to south-westerly winds veered gale-force westerly. Gusts to 58mph were reported in Lerwick and in Fair Isle and Foula.
With a filling low moving into Scandinavia, the 7th was cool, bright and showery, with fresh north-westerly winds falling light later. With low pressure over southern Scandinavia and high to the west, the 8th was a bright day with showers and occasional sunny spells. North to north-westerly winds increased strong for a time but eased later and, as showers died away, skies cleared and a cold night with a widespread grass frost followed.
South-easterly winds strengthened on the 9th and patchy rain spread from the west later, as fronts pushed in off the Atlantic, bringing a wet and windy night. The 10th remained rather cloudy with occasionally heavy rain, though south-westerly winds eased as a filling low drifted down from Iceland towards Shetland. As the low moved away eastwards, fresh northerly winds brought brighter, cooler and showery conditions on the 11th.
North to northerly winds eased and showers mostly died out on the 12th, as a ridge moved east over the area. More rain – accompanied by freshening south to south-easterly winds – spread north-east overnight as an Atlantic low pushed fronts across Scotland. These brought periods of heavy rain and a fresh to strong southerly wind on the 13th. Further rain followed overnight as southerly winds eased.
With pressure high over southern Britain, the North Sea and Scandinavia – and a depression to the west – mild, moist west-south-westerly winds blew across Shetland on the 14th, bringing misty conditions and low cloud with some patchy drizzle. Drier, brighter conditions edged north-eastwards on the 15th, as the last of a sequence of fronts cleared and mild south-westerly winds veered to a cooler north-westerly. The 16th was dry and sunny, with fresh north-west to northerly winds easing. A cool night with a local grass frost followed.
The 17th was also dry but – as an anticyclone over western Scotland slipped south-east across the UK – north-westerly winds backed south-westerly, bringing cloudier conditions. A cold front brought outbreaks of rain from the west overnight. Drier, brighter conditions followed on the 18th, as high pressure to the south extended north over Scotland and south-westerly winds veered north-westerly. After a bright start on the 19th, as an anticyclone over the British Isles declined east and a deep Atlantic low moved towards Ireland, freshening south-easterly winds brought outbreaks of rain northwards. From the 20th to 23rd, between a depression to the west and an anticyclone across Scandinavia, strong south-easterly winds persisted across the Northern Isles. With a front slow-moving near Shetland, it was generally cloudy with outbreaks of mainly light rain.
On the 24th, south-easterly winds strengthened further as a small low ran quickly north, with rain becoming heavy and persistent by evening as easterly gales developed. Winds gusted to 66mph at Lerwick and 67mph in Fair Isle during the early hours of the 25th. Heavy rain, accompanied by gale or severe gale-force easterly winds continued across Shetland, as the low tracked across mainland Scotland and a front pivoted slowly north. As the low eventually moved away over the North Sea, gales subsided early on the 26th. The day was then mainly dry with some sunshine. As pressure built from the north-west, the northerly breeze fell light and variable, with a dry, cool and mostly clear evening following. A grass frost was fairly widespread as a ridge moved east overnight.
After a dry start on the 27th, rain spread north to reach all areas by the end of the afternoon, as south-easterly winds increased fresh to strong. On the 28th rain became patchy, with strong south-easterly winds later easing light south-west to westerly. During the last three days of the month, a large and complex area of low pressure over the Atlantic, together with high pressure to the east, brought mild, moist and fresh to strong southerly winds across Shetland – touching gale-force across Fair Isle on the 30th – with trailing fronts bringing periods of rain, mainly light, but heavy on the 30th.