Author: Eric Gilbert

Sunday July 5th
The cloud that arrived overnight on Saturday morning persisted until just after midday when it began to thin and break up allowing strong sunshine to boost the temperature to 25.1C at 15.40 being 2.3C above my long-term average. Initially, the sky was clear in the evening that allowed the temperatures to drop away to a low of 14.9C at 02.07 before cloud began to drift in again after 01.00, seen on the the back rack of the radar, that minimised any further loss and in fact saw the thermometer slowly edge upwards before rising more quickly after around 07.30 when there were breaks in the cloud that allowed bursts of sunshine to break through.

Sunday arrived with total cloud cover that by 08.00 had begin to thin and disperse that saw the temperature climb to 18.7C by 08.00, making it the warmest start to a new day for a week. As the morning progresses more lengthy, strong sunshine will begin to quickly lift the temperature, which is likely to reach the heatwave threshold of 27C this afternoon.

There is now considerable certainty that we will have to endure heatwave temperatures for at least the next week with maxima reaching into the low 30s by midweek.

The forecast track of the jet stream indicates that it will begin to loop north of the UK from Monday, referred to meteorologically as an Omega block, allowing the Azores high pressure with its accompanying hot air to dominate our weather and fend off any incursion of weather fronts from the north. There are indications that by next weekend it will begin to fragment, which is likely to mean temperatures fall away a few degrees but still well above the July average with heatwave conditions likely to last until mid-July.

Skomer Island. The Wildlife Trust of South and West Wales said 52,019 puffins were documented on Skomer Island this year – 8,000 more than in 2025.

Saturday July 4th
The Azores high began to dominate our weather on Friday as the temperature began to climb well above average (+3.0C) with a maximum of 25.9C at 17.45, but not a heatwave, yet. The past night was mild with a minimum of 13.7C at 01.23 early Saturday, which was 1.7C above average. The temperature did not fall further as the night progressed as the radar showed variable, then thick cloud drift across from the northwest after midnight, limiting any further loss of warmth into the atmosphere.

The cloud was still evident on Saturday morning giving dull and murky conditions with only a very slow increase in temperature that produced a reading of 16.7C at 08.00. It is forecast for the cloud to thin and break after midday.

The forecast pressure charts indicate that the high pressure will dominate our weather for at least the next week with maxima well above average and likely to produce heatwave conditions again from Sunday. However, at the moment there is no consistent estimate how hot it might get. I found this morning the following explanation from the experts.

The focus of the uncertainty is around how hot, for how long and where we’ll be seeing the hottest conditions.

Currently, the forecast is still evolving day to day.

That means details on the westerly and easterly boundary of the heat, how extensive this will be across the UK and how long the heat will last are all changeable factors.

It will become clearer in the next 24-48 hours.

Why are the details not set yet?

Here in the UK, meteorologists look at three main sets of information to create forecasts – including the UK Met Office, and European and US-sourced data.

Over the next few days, the three versions of weather data are not aligned when it comes to the maximum temperatures we can expect next week.

Skomer Island, off the Pembrokeshire coast in Wales, is home to a record-breaking colony of over 52,000 Atlantic Puffins.

3rd July
The brisk breeze on Thursday, gusting to 20mph from the northwest, meant a cooler start to the day after cloud from the back edge of the weather front eased away, then produced a very warm day with the thermometer peaking at 24.6C at 16.02, which was 1.8C above average. By contrast, the last night was very cool, in fact the coolest for two months, since 17th May, with a minimum of 6.9C at 05.02 early Friday being 5C below average. This was due to a clear sky and the residue of the cooler air from the northwest, that is about to change.

Friday began with hazy sunshine through high cloud but the thermometer had recovered to 14.9C by 08.00 after the cool.

The Azores high has been building across the country in the last twenty-four hours with a rise of 9mb since yesterday with a reading of 1030.4mb at 08.00, which was the highest pressure since the end of May. The forecast pressure charts indicate that the high pressure will settle just off the Bay of Biscay for some considerable time and produce hot weather for a week or more with heatwave conditions arriving on Monday.

The Met Office has warned that UK waters are experiencing a long-lasting marine heatwave with a risk of hitting rare ‘extreme’ levels next week as temperatures are expected to break records again

The Met Office has issued a new ‘extreme’ heatwave warning as UK waters could reach ‘severe’ levels next week.

The prolonged marine heatwave affecting UK waters throughout much of 2026 is set to escalate next week as temperatures of 39C are forecast.

According to the Met Office, surface waters in north-west European seas are presently experiencing moderate to severe marine heatwave conditions, with numerous areas currently classified as “strong” and some “severe”.

This indicates waters have climbed to temperatures typically anticipated in August and are on average 2C above normal.
In some areas of the English and Welsh coastlines, temperatures have climbed more than 4-5C.

Specialists suggest these record-breaking temperatures are likely to have far-reach-ing consequences on weather systems, the global climate and ecosystems, triggering changes in fish populations and harming numerous marine species.

This follows the raised sea-surface temperatures which surged in recent days, partially due to last week’s exceptional heatwave, fuelled by climate change and a “heat dome” that became stationary over Europe and confined heat for several days.

I am starting a new series of pictures taken taken a few years ago on Skomer Island, just off the cast of Pembrokeshire, where a puffin colony resides.

Thursday 2nd July
After early drizzle on Wednesday the sun came out to play that boosted the temperature to a maximum of 24.3C at 15.07, being 1.4C above the early July average. The UV indices of 7.9 indicated that the UV level at its peak was well into the Very High category. The past night has been mild with the thermometer not dropping below 14.8C at 02.00 being 2.8C above average.

Thursday arrived with low cloud draping the Marlborough Downs and Savernake Forest that produced light drizzle amounting to 0.2mm. This was due to a weather front crossing the area that should be clear by midmorning when the sun will reappear and shine strongly, boosting the temperature just above the July average.

The outlook is for the low pressure to the northwest to slowly give way to the Azores High that will push across the country this evening and over the weekend that, with the high centred just to the southwest of the UK, will mean the breeze for the next few days and into the next week will come predominantly from the west or northwest.

As a result, the rise in temperature will be modified, coming over the eastern Atlantic Ocean with peak temperatures being above average but not so excessive as last week when the easterly and southeasterly breeze pushed the hot air directly from the Continent across the country. The rise in temperature, as the high becomes resident, will probably mean peak heat will produce heatwave conditions again with maxima at 27C or above. There will however, be one significant difference to the June heatwave and that is the forecast humidity will be much lower so the air will be less oppressive.

June 2026 Review

After a warm, damp start to June, with a substantial fall of rain on the 1st totalling 28.0mm, there was a significant change from the 4th as the wind veered from a southerly quadrant to a westerly direction.

This change to a cool flow of westerly air resulted in a week of below average temperatures by day. The first twelve days all had a maximum below average with the 6th being 5C below the June average. At first, the nights held just above average but sadly for gardeners, there was a significant drop from the 9th to the 11th with almost identical minima being about 2C below the June average, restricting the growth of new plants. This period brought variable rainfall from modest passing showers.

We all began to relax from the 12th as the recent track of the jet stream crossing the Atlantic pushing weather fronts across the UK made a significant change in direction. It began to loop to the north of the UK putting us on the warmer south side, this allowed high pressure to the southwest to edge over the UK and transform the weather from cool and damp to fine, warm and sunny. At last sunshine arrived that boosted the temperatures above average with 21.4C on the 13th, the first in June.

Around the 17th there were signs of a significant anticyclone developing across the Continent. The southern half of the UK was on the edge of the hot air and that lifted the temperatures well above average. The recent depression, centred south of Iceland, was still dominant, which produced occasional weather fronts and humid air that resulted in variable cloud and during the breaks strong sunshine.

It was Sunday 21st when a plume of hot air eventually arrived from the Continent and that sent the thermometer soaring to reach the first day when the heatwave threshold temperature for Wiltshire, of 27C, was exceeded.

The relentless, continuous strong sunshine pushed the temperature higher every day with a peak of 34.9C on the 25th, being 14.1C above my long-term average, setting a new record for this station for June, which surpassed my previous record of 32.2C set in 2017.

We all remember how hot it felt outside in the intensive heat, however, I thought it interesting to have an overview of how the soil, at a depth of 5cm and read every day at 08.00, responded to the wall-to-wall, excessive heat. On the 20th, the day before the heatwave arrived, the temperature was 20.4C, then 21.2C, 22.9C, 23.7C, 25.6C, 25.8C and 26.9C respectively, for the following six days. Since 2014, when this instrument was installed, the average temperature over the intervening 13 years, has risen from 15.5C to 16.3C.

As a matter of interest, the glass soil thermometer has a 90-degree angle, with the horizontal scale just above the surface, on which is the inscribed scale.

The Met Office heatwave threshold was updated ahead of summer 2022. The initial heatwave thresholds were calculated based on the 1981-2010 climatology of daily maximum temperature at the mid-point of the meteorological summer (15 July). The revised thresholds use the 1991-2020 averaging period introduced in January 2022. The geographical differences reflect the differences in climate across the UK.

This second heatwave of 2026, lasting seven days, ended on the 28th as two cold weather fronts crossed the country with a much cooler air stream following as the wind backed into a westerly quadrant. This heralded the arrival of an Atlantic weather pattern to close the month.

To get an overview of how the climate might have changed regarding these very hot days, I delved into my records and took an arbitrary, round figure of 30C. Choosing periods of five years I found that 30C or above was recorded on 5 days between 2011-2015, 19 days from 2016-2020 and 30 days for 2021-2025.

Another angle was to research on how many occasions we had endured a heatwave, a daily maximum of 27C or above for Wiltshire, for at least consecutive three days. Taking the same five-year periods, I discovered that from 2011-2015 there was 1 heatwave on each of three years, from 2016-2020 for three years had 2 heatwaves and during the last period of 2012-2025 for two years we had 3 heatwaves each year. Thus over 15 years a very clear picture of an upward trend in the increasing days of extreme heat for longer periods.

The monthly rainfall total was 66.8mm being 110% of my 42-year record or +5.3mm. The wettest day was on the 1st when nearly half the month’s rain fell with a daily total of 28.0mm. There were 17 totally dry days.

The average temperature for June of 17.85C, was 2.9C above my long-term average, which broke the previous record set in 2023 by 0.31C. Both maxima and minima contributed to this high average with the maximum 2.3C and the minimum 3.4C above average.

Wednesday 1st July
Tuesday saw the temperature by day begin to creep up again with a maximum of 23.6C mid-afternoon at 15.47 being 2.9C above average. The radar in the late afternoon indicated broken shower activity coming in from the southwest that produced just a few spots of rain that were observed at 18.30, the bulk of that rain, once again was to the northwest of our area, whilst a modest shower of light rain totalling 1.0mm arrived at 20.10.

Wednesday arrived with variable cloud that limited the sunshine but by 08.00 the thermometer had risen to 15.9C.

The tussle between the Azores high and the low pressure system between Scotland and Iceland, continues with a couple of weather front arriving across the the UK this evening pushing cloud before them and following into tomorrow morning that have the potential to produce light rain in the early hours, around sunrise time, which we won’t see.

There is now considerable confidence that we will see another heatwave arriving on Sunday when the maximum will be at least 27C, although temperatures will begin to rise from Friday into the weekend. The forecast charts indicate that the centre of the high pressure will be subtly different position compared to last week, which will result in the air stream arriving from a more westerly direction rather than from the southeast as last week, that dragged the very hot air directly across from the Continent. This next heatwave will see the hot air having travelled across part of the eastern Atlantic that will moderate the extreme heat.

June 2026 Review

After a warm, damp start to June, with a substantial fall of rain on the 1st totalling 28.0mm, there was a significant change from the 4th as the wind veered from a southerly quadrant to a westerly direction.

This change to a cool flow of westerly air resulted in a week of below average temperatures by day. The first twelve days all had a maximum below average with the 6th being 5C below the June average. At first, the nights held just above average but sadly for gardeners, there was a significant drop from the 9th to the 11th with almost identical minima being about 2C below the June average, restricting the growth of new plants. This period brought variable rainfall from modest passing showers.

We all began to relax from the 12th as the recent track of the jet stream crossing the Atlantic pushing weather fronts across the UK made a significant change in direction. It began to loop to the north of the UK putting us on the warmer south side, this allowed high pressure to the southwest to edge over the UK and transform the weather from cool and damp to fine, warm and sunny. At last sunshine arrived that boosted the temperatures above average with 21.4C on the 13th, the first in June.

Around the 17th there were signs of a significant anticyclone developing across the Continent. The southern half of the UK was on the edge of the hot air and that lifted the temperatures well above average. The recent depression, centred south of Iceland, was still dominant, which produced occasional weather fronts and humid air that resulted in variable cloud and during the breaks strong sunshine.

It was Sunday 21st when a plume of hot air eventually arrived from the Continent and that sent the thermometer soaring to reach the first day when the heatwave threshold temperature for Wiltshire, of 27C, was exceeded.

The relentless, continuous strong sunshine pushed the temperature higher every day with a peak of 34.9C on the 25th, being 14.1C above my long-term average, setting a new record for this station for June, which surpassed my previous record of 32.2C set in 2017.

We all remember how hot it felt outside in the intensive heat, however, I thought it interesting to have an overview of how the soil, at a depth of 5cm and read every day at 08.00, responded to the wall-to-wall, excessive heat. On the 20th, the day before the heatwave arrived, the temperature was 20.4C, then 21.2C, 22.9C, 23.7C, 25.6C, 25.8C and 26.9C respectively, for the following six days. Since 2014, when this instrument was installed, the average temperature over the intervening 13 years, has risen from 15.5C to 16.3C.

As a matter of interest, the glass soil thermometer has a 90-degree angle, with the horizontal scale just above the surface, on which is the inscribed scale.

The Met Office heatwave threshold was updated ahead of summer 2022. The initial heatwave thresholds were calculated based on the 1981-2010 climatology of daily maximum temperature at the mid-point of the meteorological summer (15 July). The revised thresholds use the 1991-2020 averaging period introduced in January 2022. The geographical differences reflect the differences in climate across the UK.

This second heatwave of 2026, lasting seven days, ended on the 28th as two cold weather fronts crossed the country with a much cooler air stream following as the wind backed into a westerly quadrant. This heralded the arrival of an Atlantic weather pattern to close the month.

To get an overview of how the climate might have changed regarding these very hot days, I delved into my records and took an arbitrary, round figure of 30C. Choosing periods of five years I found that 30C or above was recorded on 5 days between 2011-2015, 19 days from 2016-2020 and 30 days for 2021-2025.

Another angle was to research on how many occasions we had endured a heatwave, a daily maximum of 27C or above for Wiltshire, for at least consecutive three days. Taking the same five-year periods, I discovered that from 2011-2015 there was 1 heatwave on each of three years, from 2016-2020 for three years had 2 heatwaves and during the last period of 2012-2025 for two years we had 3 heatwaves each year. Thus over 15 years a very clear picture of an upward trend in the increasing days of extreme heat for longer periods.

The monthly rainfall total was 66.8mm being 110% of my 42-year record or +5.3mm. The wettest day was on the 1st when nearly half the month’s rain fell with a daily total of 28.0mm. There were 17 totally dry days.

The average temperature for June of 17.85C, was 2.9C above my long-term average, which broke the previous record set in 2023 by 0.31C. Both maxima and minima contributed to this high average with the maximum 2.3C and the minimum 3.4C above average.