Although Wednesday morning was cloudy, the sun broke through after midday and raised the temperature to a maximum of 18.9C at 15.49 being exactly 4.0C above the October average. The afternoon was especially pleasant as the breeze from the southwest was very light, just one occasion when the air movement reached into double figures of 11mph. The past cloudy night meant a mild night with the lowest temperature reached at midnight. Usually the temperature slowly drops in the early hours but in fact it rose to 12.0C just after 02.00 before falling back to 10.7C again at 08.00.

Thursday dawned with misty conditions from the moist, mild southerly airstream. At 07.00 I observed that fog had briefly drifted across and masked the Marlborough Downs and Savernake Forest but just after 07.30 this had disappeared.

The barometric pressure over the past twenty-four hours has varied little, just a drop of 3mb since Wednesday, and at the moment is steady. There is much more confidence in the track of Storm Amy that is likely to close in on the northwest over the next two days. This will bring us spells of very wet and windy conditions but modest compared to the conditions over Scotland and the Northwest. The centre of Storm Amy is forecast to have a very deep centre pressure of 962mb within twenty-four hours and deepen significantly by midnight on Friday to an extremely low pressure of 939mb. At that time, we will be some distance from the centre of the storm but the pressure here will drop a significant 25mb, which is exceptional over a twenty-four hour period, with a forecast pressure of 1000mb.

September 2025 Review

After the hot months of the past summer, September arrived with weather more resembling autumn.

The first week brought sunshine and showers with much welcome rain on the 2nd and 3rd, the two-day total of 35.8mm was more than the August total. The notable feature also was the flow of air from the Continent that kept the maximum and minimum temperatures around or just above average.

The second week was dominated by a series of depressions to the northwest that produced variable quantities of rain and subdued temperatures due to the variable cloud cover. The maxima from the 10th to the 16th were all below average with often strong south-westerly winds, a peak of 28mph was logged on the 14th.

Following so many dry days in the past six months it was a significant change in the weather pattern to have eight consecutive days with precipitation that took the monthly total above my 41-year average by the 14th, the first since February.

The 18th and 19th were memorable for a south-westerly airstream that brought us fine warm air from around the Azores region, which resulted in a maximum of 25.0C during the Friday afternoon making it the warmest day since 15th August.

A significant change in the weather arrived during the evening of the 20th. This was due to the recent low pressure system migrating eastwards over Scandinavia and allowing a large area of high pressure to edge in from the Atlantic that began to build. As a result, the wind veered from the recent southwest to north over the following twenty-four hours. The airstream circulating clockwise around the high pressure, as it does, was originating near Iceland before descending south across the UK, thus a much cooler airstream.

The last week brought us very cool days and even cooler nights under the influence of the northeasterly airstream that brought Arctic air. There were nine consecutive days with maxima below average, the coldest being 13.6C on the 26th, which was 5.4C below my long-term average.

The nights were cold due to a combination of the cool air originating from the north, clear skies and calm conditions with no breeze to stir up the atmosphere. We just missed an air frost, although minima of 0.4C and 0.7C in the early hours of the 23rd and 29th resulted on a short-lived ground frost.

The last two days brought sunny intervals and recovering temperatures as an Azores High began to build linking up with the old anticyclone, then over Scandinavia. This resulted in the first above average maxima of 19.5C since the 19th.

The rainfall for October amounted to 79.5mm, which was 119% of my 41-year average, or plus 13mm, measured in my 5” copper Met Office rain gauge. It was the first above average monthly rainfall since February. This was such a contrast to the very wet September of 2024 when 221.4mm was recorded. There were 12 totally dry days with the wettest occurring on the 3rd when 20.6mm was logged.

There were considerable variations in the daytime temperatures, varying from a peak of 25.0C on the 19th to a very cool 13.9C on the 26th under total cloud cover and a northeasterly breeze. The nighttime minima also gave us wide variations with a warm night on the 18th when a minimum of 16.8C was recorded that contrasted against 0.4C in the early hours of the 23rd when a ground frost occurred, if briefly. The average temperature for September was 13.8C, which was 0.4C below average but interestingly the same as in 2024