Appendix 6 - Season 2024-25 Weather Summary
Argyll and Bute Council · 11 September 2025
Back to Environment, Development and Infrastructure Committee — 11 September 2025 and its agenda
Text extracted from the council's PDF. Layout and reading order may differ from the original.
Page 1
Appendix 6 Season 2024-25 Weather Summary OCTOBER 2024 Mild conditions, initially with prolonged spells of rain still making their way in from the Atlantic, but a switch to a more northerly air flows on the 9th brought colder Arctic air into the UK. On Oct 9th, RSTs dropped down to Minus 1.4C Salachray , Minus 1.2C Leanach and Minus 1.1C Blaran on dry surfaces. A little less cold on the 10th with the return of rain, but drier and clearer conditions overnight saw RSTs dip close to zero more locally. Whilst the 11th and 12th were mild and wet once more, clearer skies on the night of the 12th saw RSTs falling below zero again with Minus 1.4C Salachray and a range Minus 0.9C – 0.5C for Mid-Argyll and Lorn sensors. The following week was unsettled, with areas of low pressure pushing in from the Atlantic resulting in prolonged spells of rain and blustery winds. The 15th began dry, however that quickly changed as the overnight period saw heavy downpours, some thundery and persisted through to Wednesday 16th. It became drier on the 17th as frequent showers fed in from the west. Further bouts of rain pushed in from the Atlantic on the 18th/19th but on the 20th, the first named storm of the season – Storm Ashley – brought very strong winds gusting 60- 70mph during the day. Not only was it very windy, but torrential downpours swept in from the west too. This affected North Argyll mainly, with coastal flooding in Oban and Tobermory and tide bourn debris affecting the Slate Islands of Easdale and Luing. Many watercourses were affected by strong flows for a time but nothing as significant as Oct. 2023. The 21st saw drier and less blustery conditions, albeit with showers feeding in from the west. It was a mild week, and RSTs remained above zero. The 22nd saw sunny spells and showers, with these showers feeding in on brisk westerly winds. Further showers and longer spells of rain moved in from the Atlantic over the next few days with RSTs remaining well above zero. Whilst most of the rain was on the lighter side, a heavier band of rain pushed in from the west on the 26th, with clearing skies and colder conditions following in from behind. High pressure settled in for the rest of the period with cloudy skies and a lot of light rain and drizzle around through to Nov 1st. NOVEMBER 2024 The start of official winter standby was subject to autumnal conditions for the first week with rain of varying intensity and duration as weather fronts in mild southerly air, passed over Argyll. Minimum overnight RSTs remained in the range Plus 5C to 10C through to 16th , with a slight dip neared to zero on 11th. A change in air flow on 17th allowed RSTs and Air to fall sub-zero overnight, with precipitation turning more wintry in nature. Widespread frosts and light snow affected the area , with RSTs Minus 6C to Minus 1 C through to 20th. Continuous subzero periods developed with the highest RST at Leanach at 13:00hrs on 18th recorded as Minus 2C before dropping again overnight, with the lowest overnight RST of the season so far, Minus 8.2C recoded at Leanach at 03:00hrs on 20th. Leanach and Blaran
Page 2
sensors recorded continuous 24hr sub-zero RSTs respectively on 20th &21st and 19th & 22nd. Sleet and Snow fall, of varying intensity continued throughout this period, with the deeper accumulations on higher, inland routes. Named Storm Bert passed over the area between 22nd – 25th with maximum wind gusts of 73.2mph recorded at Ballygrant on 23rd and 74.5mph at Dervaig on 24th, before a further drop in RSTs, partially on 27th and 29th, with all sensors subzero RSTs early on 28th, in the range Minus 3.3C Ballygrant to Minus 7.2C Leanach . Named Storm Conall passed through southern England on 27th but there was little effect in Argyll, with the month ending in a dramatic increase in overnight minimum RSTs, from Minus 7.2C on 28th to Plus 6.8C by 30th, as rain returned as the prevailing weather condition. DECEMBER 2024 The mild conditions continued into December, with overnight minimum RSTs Plus 8 to 11 Deg C with rain heavy at times overnight into 2nd. Conditions changed in northerly air streams with marginal positive RSTs before developing in the range Minus 4.6Deg C Leanach to Minus 0.9C Dervaig on morning of 3rd with more sub- zero RSTs on 4th Minus 2.9C Accurrach to marginal Zero C Island sensors . Intense rain overnight 4th – 5th caused localised flooding in Bute, Cowal and Lomond, with further marginal nights into 6th and 7th before the arrival of named Storm Darrah. The storm centre passed over central England with limited effect as far north as Argyll. Kintyre and Lomond experienced intense but localised rain, with watercourses overtopping and drainage systems surcharging early on Saturday 7th, with resultant partial wash-out of two bridge foundations on B842 Campbeltown – Carradale. Snow farther north in Argyll was light, short in duration and confined to higher level sections of the network. Heavy frosts developed over the following nights, with RSTs Minus 6.5C Leanach, Minus 6.1C Blaran and Minus 5.9C Salachray through to Minus 2.7C Lochdonhead, by 06:00hrs Monday 9th with continuous 24hr sub-zero on many inland sensors through to Tuesday 10th , with the “mildest” RST at Salachray at 12:00hrs Mon 9th of Minus 3.5C before dipping again to Minus 7.3C early on Tuesday. Cloud cover allowed most sensors to partially recover by sunrise, however many places remained sub-zero in shaded sections with persisting hazards, even after repeat treatments. RSTs again stayed sub-zero over the next 24hrs at some locations with Leanach Minus 7.9C at 05:00hrs, Accurrach Minus 6.5C 02:00hrs on 11th with sensors south and east Minus 5.9 to Minus 3.6C around 22:00hrs on 10th before improving towards dawn. Island sensors stayed positive RST minimum Plus 1.8C to 3.8C. as cloud and fog conditions developed early morning. The gradual Eastward drift in improvements in overnight minimum RSTs continued into 12th , with only central mainland sensors sub-zero , Salachray Minus 1C, Haul Rd Minus 2.4C, Accurrach Minus 5.2C and Leanach Minus 6.7C, although in some areas minimum air temperatures were marginally lower in fog. By the morning of 13th only Accurrach and Leanach had gone marginally sub-zero RSTs overnight, as weather fronts moved in from the North
Page 3
West. The forecasts did however, continue to indicate long periods overnight where sub-zero RSTs and Air were possible, mainly in the northern mainland domains. Mild and wet conditions prevailed 14th – 17th , showers or longer spells of rain, as weather fronts passed over the area, in generally southerly airflows. RSTs improved From Plus 3 to 6 C on 15th to Plus 7 to 9C on 16th / 17th. Heavy rain through central Argyll recorded 24hrs totals of 30-32mm by the morning of 18th , with strong winds overnight, resulting in a maximum gust of 66mph recorded at Dervaig at 04:10hrs. There was a brief change to Northerly airflow 18th- 19th, which allowed RSTs to drop sub-zero and showers turn more wintry early morning, with marginal RSTs Minus 1.1C Haul Rd , Minus 0.9C Leanach. This trend continued on 20th with sub-zero RSTs confined to central sensor sites Minus 1.9C Leanach to Minus 0.3C Cnoc an Rath. Milder conditions prevailed as the next warm from passed over on 21st accompanied by strong winds, gusts of 70mph recorded at Dervaig 12:00hrs , before the last subzero RSTs of the year Minus2.5C morning of 22nd and Minus 2C on the morning of 23rd Dec. although generally conditions were wet and mild for the time of year. The Christmas week through to the end of the month saw RSTs drop no lower than Plus 3C and generally in the range Plus 5 to 9C. High winds returned from 27th with gusts of 74.3mph recorded at Derail 06:00hrs on 29th. This resulted in several incidents of fallen trees affecting routes , where waterlogged roots allowed overturning. JANUARY 2025 The start of the New Year heralded the end of the mild and wet conditions of the previous two weeks, Minium RSTs by 08:00hrs on 1st were marginal Plus 0.1Deg C at Accurrach to Plus 4.1 C at Ballygrant which changed over the following 24hrs with Mininum RSTs Minus 6.6C at Leanach to Minus 2.4C Lochdonhead. Overnight temperatures fluctuated for the next three days with minimum RSTs between Minus 3.6C and Minus 7C with milder conditions in intermittent clear spells early afternoons. A more widespread frost developed from Sunday 5th into Monday 6th January, with clear sunny conditions during the day and open skies overnight generally, with isolated showers. A widespread frost developed into Tue 7th but cloud cover and intermittent wintry showers allowed temperatures to fluctuate. Light snow overnight and a hard frost on Wed 8th resulted in RSTs of Minus 7.1C Leanach , Minus 5.8C Salachray , Minus 5.4C Haul Road through to Minus 1.6C Dervaig , with this sensor being the only one to retain a positive air temperature overnight, in generally northerly air flows with any showers confined mainly to western coastal areas and outer islands. All sensors dropped sub-zero by 17:00hrs, minimum RSTs of Minus 9.2 C Leanach at 08:00hrs Thu 9th with near continuous subzero for next 24hrs through to the coldest recorded RSTs of the season so far, on Friday 10th , Minus 10.2C Leanach and Minus 8.0C Accurrach at 08:00hrs , with Blaran Minus 9C at 03:00hrs and Haul Road Minus 7.4C at 05:00hhrs before slight recovery. Sat 11th saw the start of a change, with cloud developing and minimum RSTs of Minus 7.4C Accurrach , Minus 7.0C Blaran and Minus 5.9C Leanach as winds turned southerly
Page 4
through to Sunday 12th with only localised sub-zero the previous evening and all sensors marginal positive by 08:00hrs. Heavy rain affected the area, as a warm front passed over Argyll bringing mild southerly airflows, with RSTs Plus 7C to 10C by Monday 13th 08:00hrs. The following week was variable cloud and rain, before a sunny day and clearer night in parts into Thu 16th, with sub-zero RSTs Central/North sensors only, minimum Minus 0.3 to 1.1 C around 06:00hrs. The following week saw variable amounts of cloud and precipitation, with positive minimum RSTs until 22nd, Stewarton Minis 1.2C in a overnight clearance, with northern mainland domains dropping to between Zero C and Minus 1C briefly on the mornings of on 23rd and 24th. However, the more significant event in this period was the passing of Named Storm Eowyn over the area. High winds developed overnight into the early hours of Friday 24th with maximum gusts recorded from mid-morning onwards at the more exposed sites to the Westerly gales. Maximum Gusts recorded at Haul Rd-Lomond 69.1mph at 10:50hrs, Clachan Hill-Kintyre 81.0mph at 12:40hrs, Ballygrant-Islay 83.2mph at 11:40hrs, Stewarton-Kintyre 88.5mph at 12:20hrs, with the highest gust recorded at Dervaig-Mull 98.2mph at 16:30hrs, Fri. 24th. before the main storm centre passed East into central Scotland by afternoon and overnight allowing winds to ease by Saturday 25th. Winds turned northerly with overnight RSTs dropping in the range Zero C to Minus 3.8C from 25th through to 29th. The later season pattern of RSTs dropping overnight to minimum temperatures around dawn, continued with a low of Minus 4.5C at Leanach 08:20hrs on 30th, with all sensors subzero by early morning. The last 2 days of the month were variable, with clear spells bringing sun during the day and marginal frosty conditions overnigh, between bands of rain, as weather fronts moved east over the area. Localised Minus 0.7C Leanach and Minus 0.2C Blaran on the morning of 31st before a final cold snap in northern mainland and island domains, down to Minus 3.4C to Minus 1.1C up to mid-night , before all sensors improved to positive RSTs by 06:00hrs Saturday Feb 1st. FEBRUARY 2025 The remnants of a cold snap on the evening of 31st Jan had dissipated by 06:00hrs Sat 1st with a return to mild southerly airflows and frequent bands of showers passing over the area. Clear spells during the afternoons of 1st and 2nd but overnight RSTs remained positive but marginal, minimum Plus 1.4C to 1.6C evening, before improving into Mon 3rd. Marginal 50mph+ gusts and heavy rain on Monday and Tuesday led to clearer conditions , sunny periods by day and frosty nights as the week progressed, with 50mph gusts recorded daily at Dervaig sensor. All sensors were sub-zero into Friday 7th in the range, Minus 4.8C Leanach , Minus 4.6C Accurrach, through to urban sensors Lochgilphead Minus 1.2C and Minus 0.6C Helensburgh. The weather over the weekend and Monday 10th remained that of generally clear skies with sunny periods by day and frosts overnight, with very little in the way of precipitation. RSTs dropped within the range Minus 5.4C to Minus 4.7C Blaran, Leanach and Accurrach to Minus 1C at other rural sites, before partially recovering on 10th, Minium Minus 2.2C Blaran and Dervaig. Cloud cover over most
Page 5
of the area on Tue 11th kept RSTs milder than previous days, a slight dip subzero the previous evening at Northern censors, returned to positive RSTs all sites prior to midnight, with air temperatures generally 2-3 Deg C milder. This pattern of marginal conditions was repeated through to 16th, with only sensors in the north and central mainland dipping marginally sub-zero Minus 1.6C to Minus 2.4C as the lowest RSTs overnight. There was a brief milder period overnight into 17th with only Leanach dipping to minus 0.2C just before sunrise 08:00hrs. There were further dips in overnight RSTs on 18th and 19th, with associated isolated wintry showers, before all sensors showed an improvement, albeit associated with wet and windy weather. Gusts of 63.1mph were recorded at Ballygrant, 70.0mph at Dervaig on the morning of 21st. heavy rain on Friday gave way to a clearer spell Saturday 22nd before the next weather system with heavy rain, most of the day Sunday 23rd. Wind direction was southerly however, which resulted in very mild conditions overnight, air temperatures closer to daytime averages for the time of year. The mild, predominantly southerly, air flows continued through to 26th, minimum RSTs overnight fluctuating between Plus 3.5C and 2.1C, with cloud cover and spells of occasionally heavy rain throughout. On Wed 26th winds turned Northwesterly, allowing a small dip in RSTs early morning, Leanach Minus 0.5C and Accurrach Minus 0.1C around 04:00hrs before a clear sunny day, with occasional showers which cleared late afternoon. RSTs had reached double figures at some sites by mid-afternoon in clear skies, allowing a sharp drop in temperatures overnight into Thu 27th , with all sensors subzero by dawn. RSTs ranged from Minus 3.7C Leanach and Minus 3.4C Salachary , through to Minus 1 C Stewarton and Dervaig . Sunny and clear conditions on Thu 27th allowed air and surface temperatures to recover quickly. Showers developed in the afternoon , some sleety, before a further clearing overnight into 28th allowed temperatures to drop again steadily towards dawn , with minimum RSTs Minis 1.8C Cnoc-an-rath Bute ,Minus 1.6 C Salachary- Mid-Argyll , Minus 1.3C Stewarton -Kintyre and Minus 1.0C Leanach-Cowal and Blaran -Lorn E. Cloud cover in the north allowed some sensors in towns and on Mull to remain positive and the building cloud throughout the final day of the month, although dry, resulted in milder conditions overnight into 1st March. MARCH 2025 A warm front with cloud and rain ushered in the last full month of the standby period before clearing to sunny spells and a marginal drop in the north of the area in clear skies overnight. Sensors at A886 Leanach , A816 Blaran , A819 Accurrach and A817 Haul Rd all dipped to between Plus 1C and Zero but only A816 Salachary recorded a subzero RST, Minus 1.3C briefly at 06:00hrs Sun 2nd . There them followed a mild period from the night of 2nd through to 9th March. Weather conditions were a mixture of clear sunny spells and periods of occasionally heavy rain, as weather fronts passed over the area. Airflows were generally southerly and mild for the time of year. Minimum overnight RSTs were fairly constant at Plus 3 or 4 Deg C mainly centred around northern mainland sensor sites with other sensors one or two
Page 6
degrees milder. The wind direction changed to turn progressively northerly, with minimum RSTs before dawn on 10th March Plus 1.5 DegC – Leanach , Plus 1.9C - Stewarton and Haul Rd. Widespread frosty weather returned from Tuesday 11th March , with RSTs dropping early morning to Minus 3.7C - Leanach , Minus 3.2C to 3.0C Salachray , Blaran , Accurrach through to Minus 0.7C Lochdonhead-Mull , before RSTs recovered in clear sunny conditions. Variable cloud held temperatures up slightly on 12th with minimum RSTs Minus 2.2C – Leanach through to Minus 0.2C Accurrach , mainly in Northern inland areas before a further clearance overnight into the morning of 13th allowed RSTs to drop again to Minus 4.6C Salachray, Minus 4.3C Blaran, Minus 4.2C Leanach through to Minus 1.2C Dervaig-Mull , with urban sites Minus 1.2C Oban to Minus 0.4C Helensburgh. A minimum air temperature, just before dawn on 13th , was recorded as Minus 4.8C at Salachray 07:00hrs. This pattern of reduced freeze and then a return to Minus 4.5C under clear skies, was repeated Fri 14th , Sat 15th and Sun 16th with a change in wind direction over the weekend, with localised showers from time to time. This brought milder conditions, than those forecast, with Minimum RSTs 07:00hrs on Monday 17th Plus 2.5C Accurrach to Plus 5.4C Dervaig. Cloud cover was variable over the next week, with periods of rain between longer spells of clear skies. This brought sunny periods and higher temperatures to road surfaces by day but allowed RSTs to steadily drop overnight, to reach minimum temperatures in the period 05:00 to 09:00hrs daily through to 20th. Minimum RSTs developed early morning through to dawn, northern domains only on 18th Minus 2.2C – Accurrach to Minus 0.3C – Dervaig. This pattern was repeated, in clearer air on the morning of 19th , Minus 2.9C-Leanach , Minus 2.8C-Accurrach through to Minus 0.2C-Dervaig and some urban sensors. A similar, slightly milder pattern developed on the morning of 20th, Minus 2.4C-Leanach, Blaran and Accurrach, with RSTs recovering from lows around 07:00hrs, after sunrise. Precipitation was isolated and limited to small bands of rain passing over the area in predominantly Easterly winds. Conditions changed from 21st, after the Spring Equinox, with periods of more persistent rain and cloudy conditions in milder airflows from the South and East. RSTs were significantly milder with overnight minima Plus 2.5C initially, climbing to Plus 5 to 6C, with a slight dip on the morning of 24th to Minus 0.1C RST at Blaran. The clear skies allowed RSTs to recover, with highs recorded at A817 Haul Rd PLUS 29.5C at 12:40hrs, Cnoc-an-Rath, Bute PLUS 30.2C at 13:30hrs. This trend towards milder Spring like conditions returned on the morning of 25th with minimum overnight RSTs recorded as Plus 6.6C to 9.3C. around 06:30hrs. Weather fronts brough bands of rain and clear spells which gave variable conditions up to the end of the month Heavy and persistent rain arrived on the Wednesday evening 26th and continued into Thursday 27th. Air temperatures were marginal, approaching Zero Deg. C allowing Hail to develop in some showers on Fri 28th between sunny intervals. The month ended with the start of a dry period, due to the development of a high-pressure system over the country, with clear sunny conditions by day on 31st with the start of lower overnight temperatures in clear skies.
Page 7
APRIL The “unseasonably” early spring weather continued into the final weeks of the standby. A high-pressure system sat over the country and deflected southerly and westerly winds and their associated weather fronts. Conditions were generally clear and sunny throughout the day with clear skies overnight leading to sharp falls in temperature. Minimum RSTs generally developed between 06:00-08:00hrs each morning, before recovering after sun rise. RSTs were still marginal dropping to Plus 2 to 3 Deg C, generally on several nights in the first full week of April. The lack of precipitation over the period allowed road surfaces to stay generally dry, with just light dew fall and very limited seepage from verges after the dry period from the end of March. Consequently, there was little risk of the formation of road surface hazards, with none recorded at any weather sensors during the period. As the high-pressure system moved away to the South East over Europe, over the weekend 12th /13th this allowed south-westerly winds to bring weather fronts in off the Atlantic. The air temperatures were still marginal in cloudier conditions with frequent bands of showers passing over the area, including localised Hail showers on Sunday 13th in the Mid-Argyll area. Sunny spells between showers continued through the final week, towards the end of official Winter Standby mid-day on Thu 17th , change of standby shift – start of Summer Standby arrangements. The overnight temperatures continued to be marginal for the remainder of April, with Accurrach dropping briefly to Minus 0.3Deg C RST at 06:20hrs on 17th before the start of the Easter Holiday weekend but as there had been no precipitation, surfaces were dry and hazard free. Ballygrant sensor dropped to Plus 1.9Deg C on Tuesday 22nd but generally RSTs improved in mixed cloud cover through to end of April , with minimum RSTs Plus 4 - 5 Deg C before improving to double figures for minimum overnight / early morning temperatures by the end of the month. End of 2024-25 Weather Summary.