Wednesday 1st October
Tuesday, the last day of September, was a very pleasant dry and warm day under the ridge of high pressure that produced many hours of sunshine that lifted the thermometer to a maximum of 19.5C at 14.39. This peak was 0.5C above average and it was the warmest day since the 19th. The residual warmth and encroaching cloud in the early hours of Wednesday meant the minimum of 5.3C was logged in the early hours at 01.22. The large, fragmented weather front to the north had a tail of thin broken cloud that saw the thermometer rise again to reach 7.8C by 08.00.
The start to Wednesday revealed a cloudy sky from the tail of the weather front that produced a few drops of rain, not measurable, at 07.50. By 09.00 the cloud was beginning to thin and the sky to brighten.
There is now more certainty in the track of ex-hurricane Humberto. The forecast track takes it up the west coast of Ireland and towards the west coast of Scotland that is going to bear the brunt of the stormy conditions. The centre of the ex-tropical storm is forecast to be very deep with a barometric pressure reading of 945mb Friday evening.
The cloud over southern England will build on Friday with precipitation late Friday night into the early hours of Saturday. At the same time the winds will begin to strengthen significantly probably reaching in excess of 40mph on high ground.
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