Category: Commentary

Tuesday 25th August
Monday gave us a very pleasant day with strong sunshine, between the breaks in the variable cloud, that resulted in a maximum of 22.6C at 15.04, which was exactly 1C above the late August average. The past night was mild, the warmest for five nights, with a low of 13.0C at 05.21.

Tuesday arrived with welcome sunshine to start the new day, muted at first due to variable cloud on the eastern horizon, that resulted in the thermometer climbing to 15.9C by 08.00 making it the warmest start to a new day at that time since the 18th.

The current rain radar shows much rain over Devon and Cornwall and some near Bristol. However, crossing the Channel towards the south coast, arriving from the south east, is a large area of broken shower activity. At the moment the likely track takes this west of our area, so a dry day is likely.

The current and forecast pressure charts show a complex picture of low pressure systems moving towards the UK over the next few days. At the moment, the nearest is over the Bay of Biscay and is currently edging towards the UK with another towards the northwest. Various weather fronts from the disturbed area will be pushed across the UK, amounts of precipitation are difficult to predict. At the moment, the consensus of opinion is that up to the weekend any precipitation will be in the form of light showers. However, there is the possibility of heavy, more prolonged and thundery showers over the weekend as the areas of low pressure coalesce and close in on the country.

Headlines in the press this past month have highlighted the extreme temperature for the UK of 30C, and its frequency this year and over recent years. Once again I have analysed my data over three five-year periods to examine the local situation. Between 2011 and 2015 there were just five days when 30C was reached or exceeded, from 2016-2020 there were 19 days and from 2021-2025 a total of 28 days, a clear rising trend over that period of 15 years. This year so far there have been 19 days when 30C was reached or exceeded. The peak this month was 35.9C on the 13th being a significant 14.3C above my long-term August average.

Thunderstorm warnings issued as warm and humid conditions give way to heavy rain and thunderstorms
Author: Met Office

14:07 (UTC+1) on Tue 25 Aug 2026

Yellow warnings for thunderstorms have been issued for parts of England and Wales on Wednesday and Thursday, as warm and humid conditions bring an increasing chance of heavy showers, thunderstorms and longer spells of rain.

Many areas will see further warm and dry weather on Tuesday, with temperatures widely reaching the mid to high 20s Celsius across England and Wales. However, isolated showers and thunderstorms across southwestern parts are expected to become more widespread and develop across England and Wales from Tuesday evening and overnight into Wednesday. This brings the potential for longer spells of rain and heavy, sometimes intense downpours, frequent lightning and localised disruption.

On Thursday, widespread slow-moving heavy and thundery rain is expected to spread north across the UK, bringing the potential for prolonged periods of rainfall in some areas. These areas could therefore see significant rainfall totals over several hours, increasing the likelihood of localised impacts from heavy rain and thunderstorms.

Met Office Chief Forecaster Steve Willington said: “As we move into Wednesday there is a growing risk of heavy rain and thunderstorms, with warm and humid air helping to trigger heavy showers and thunderstorms. Some places could see significant amounts of rain falling in a short period of time, bringing the potential for localised flooding, travel disruption and frequent lightning.

Monday 24th August
On Sunday the temperature recovered considerably, after a few cool days, that saw the thermometer rise to a maximum of 24.5C at 16.14 being 2.9C above average. Under clear skies and totally calm conditions after 22.30, the past night has been very cool with the thermometer sinking to a low of 8.3C at 02.28. This minimum was 3.5C below average and the fourth consecutive below average minimum.

In the early hours of Monday, radiation fog had formed in the River Og valley, the Marlborough Downs and Savernake Forest could be seen above the ribbon of fog. As the temperature dropped significantly the greater moisture in the air around the river condensed that took until 07.15 to evaporate.

The recent high pressure is slowly edging eastwards but will bring us fine, dry weather for today and Tuesday with the breeze strengthening this afternoon and veering into the east. The next couple of days will be warmer as the breeze from the east will contain some warmth from the Continent, coming around the southern edge of the anticyclone, that will by then be centred over Scandinavia.

The low-pressure system, currently off the Iberian coast, will edge closer but not begin to have any major influence on our weather until Wednesday when it will produce a significant change in wind direction, to come from the south or west-southwest, arriving from the Atlantic. This change in wind direction will mean higher humidity after the air stream has crossed the sea, coming in from the Atlantic, bringing with it cloudier conditions. At the moment, the major weather forecasters are giving very different projections as to how such rain might arrive towards the end of the week from the several weather fronts that are forecast to cross the country.

By Thursday the depression will likely be centred over the UK producing unsettled conditions with variable cloud and uncertain amounts of precipitation.

Sunday 23rd August
After a sunny morning on Saturday a little variable, fair weather cloud did bubble up, but not as much as on Friday, which was why the maximum of 21.8C was logged late afternoon at 17.38 and just above the average (+0.2C) after the cool day on Thursday. The past night under a clear sky and the cool air stream from the northeast saw the thermometer drop away to a low of 6.3C at 06.04 being 5.4C below the late August mean.

Sunday began with strong sunshine that lifted the temperature to 12.6C by 08.00, which made it the coolest start to a new day this month. As the ridge of high pressure slowly relocates to the east the wind will veer from northeast to east as the day progresses, but be very light. The light breeze dropped out after 02.00 this morning. Today will probably see a similar pattern to the past two days as light cloud will probably bubble up during the afternoon. The barometric pressure today at 08.00 read 1026.2mb, the highest all month, and rising slowly.

The high pressure, ridging in from the southwest, will maintain the dry and fine weather on Sunday and probably until Wednesday with maxima returning to just above the August average. The low pressure off the coast of Iberia is forecast to edge towards the UK over the next few days. By Wednesday the forecast charts indicate five separate mini centres of low pressure to the west that by Thursday will have joined forces and bring us a cloudy and possibly very wet day that might contain thunderstorms. This realignment of weather systems will see the wind make a significant change in direction to come from the south, which will dictate our weather over Thursday and Friday bringing unsettled conditions.

From time to time over the past week or two I have seen headlines that suggest there could be another heatwave in September. I have seen nothing in the meteorological data that at this time indicates that temperatures might rise very high again. However, as a matter of interest I have analysed my statistics when the heatwave threshold of 27C for Wiltshire has been equalled or exceeded over the past fifteen years. Taking three five-year spans I found that from 2012-2015 there were 15 days, the period 2016-2020 the heatwave conditions totalled 57 days and from 2021-2025 there were 76 heatwave days. A distinct upward trend in the occurrence of heatwave days is obvious. The year with the highest number of heatwave days was 2028 with 25, followed by 2025 with 21. So, how many this year so far – 37!

Saturday 22nd August
After a fine morning on Friday the cloud began to thicken after around midday, as forecast, that limited the rise in temperature, which, combined with the cool northerly breeze, meant a maximum of only 19.2C at 13.10. This high was 2.4C below my long-term August average and the first below average maximum since 12th June, over two months ago. Under the cool air stream and clear skies a minimum of 7.4C was logged at 06.14 early Saturday, just after sunrise in Marlborough at 06.03, which was 4.4C below average.

Saturday arrived with the return of strong sunshine, after the cold night, that had lifted the temperature to 12.7C by 08.00, which not surprisingly, made it the coolest start to a new day at that time this month. The breeze is still coming from a cool northerly quadrant, however, with much greater sunshine this morning the temperature should recover to reach a maximum close to the late August average. However, the forecast cloud radar indicates that as yesterday, cloud will drift down from the north or northeast after around midday thus limiting the rise in temperature.

The high pressure has been pushing a ridge across the country this past twenty-four hours with a significant rise of almost 12mb, almost equaling the highest pressure this month, currently reading 1022.8mb at 08.00. This will result in a quiet, fine and dry weekend that will probably last over Monday.

As the high pressure relocates and edges towards the Continent, the air steam will veer a few degrees and come from the east or southeast tomorrow that could waft in some warmer air from the near Continent, gradually lifting the maximum a few degrees above average over the next three or four days.

Lurking down to the southwest is a depression that is circling around and edging eastwards at the moment. The forecast pressure charts indicate that it might join up with a mate near Iceland and move in over the UK from around Wednesday. If that scenario does in fact occur, we would have a significant change in our weather midweek to unsettled conditions with likely significant rainfall. This needs watching!

Friday 21st August
There were numerous showers drifting across the country on Thursday but as usual, they were averse to dropping any significant precipitation on Marlborough. There were a couple of times when for a minute a few drops dampened the ground mid-afternoon and early evening that amounted to 0.6mm. However, as soon as the sun reappeared the ground dried up rapidly. The high of 22.2C was logged at 14.30 being 0.6C above average whilst the low of 9.4C was 2.4C below average, recorded at 06.37.

Friday at first light revealed that a bank of fog had formed in the early hours due to the recent moisture in the air condensing as the temperature dropped, that included thicker radiation fog in the River Og valley. By 06.15 the visibility across the River Og valley was restricted to about 400m whilst less dense towards Savernake Forest. By 06.30 the sun had begun to creep above the fog bank and visibility slowly improved. By 08.00 the thermometer had risen to 12.9C making it the coolest start to a new day at that time all month.

The breeze today will be less strong and come from a northerly direction, circulating around the top of the high pressure, that will produce a cool day and probably the first day this month with a maximum below average. The forecast charts indicate that a large area of cloud will drift down across the country from the Northwest today, probably from around mid-day, from the back edge of the departing low pressure system. This will limit the sunshine and thus the rise in temperature.

The anticyclone has been slowly building over the past twenty-four hours, as the low pressure moves away eastwards towards Scandinavia, which will continue over the weekend. The centre of the high pressure tomorrow will be over the UK that will give us a fine, dry and slightly warmer couple of days, back to around the average for late August.

The soil temperature over recent days, positioned at a depth of 5cm and read daily at 08.00, has been a good indicator of how warmth has been leaving the ground. The last four mornings have read 21.6C, 19.2C, 17.5C and 15.7C respectively, after a high of 24.2C on the 13th. This was principally due to lower night temperatures combined with the minimal rainfall moisture evaporating into the atmosphere and in doing so taking a little warmth with it.

There have been comments over the past month or so of the El Niño weather phenomenon building in the Pacific. This item was published recently.

Ben Rich, Lead Weather Presenter and Mark Poynting, Climate Journalist

5 hours ago

The El Niño event that is developing over the Pacific Ocean is likely to be the strongest in living memory, the Met Office has warned.

The powerful natural climate phenomenon pushes up global temperatures and can increase the risks of extreme weather.
Added to the effects of human-induced climate change, the Met Office is warning that it is “very likely” to mean 2027 is the hottest year on record.

There is growing evidence that weather patterns around the world are already being affected, with below-average monsoon rains in India and suppressed hurricane activity in the Atlantic Ocean.

El Niño could put the UK at greater risk of a wet, stormy autumn.

“We should be clear that this is an unprecedented event”, said Prof Adam Scaife, head of long-range forecasting at the UK Met Office.

“I have never seen an El Niño signal this intense in our forecasts.”