Author: Eric Gilbert

The relentless heat continued to build on Thursday reaching a maximum of 30.7C late in the afternoon at 16.51 being a significant 10.1C above my long-term average. It was also the hottest day since 19th July 2024 when the exact maximum was recorded. Not only was it hot but the air was very dry with the humidity very low with an exceptional minimum of 38% logged at 17.54.

A thin veil of cloud was observed drifting across from the west around 17.00 that meant the sun became more variable and weaker in strength. This cloud cover thickened just after midnight when looking back at the cloud radar. This meant that the past night was less cool with a minimum of 14.4C at 05.20, being 4.2C above average, as the cloud minimised the loss of warmth into the atmosphere, compared to previous nights.

The start to the new day on Friday revealed muted sunshine as the cloud limited the strength of the sun. The thermometer had risen to 19.3C by 08.00 and stabilised there for quite a time. There was also a light breeze from an easterly quadrant that meant it felt less oppressive first thing.

In contrast to the heat and strong sunshine this week, the Met Office yesterday sent out an email inviting the public to submit their suggestions for storm names for the upcoming 2025-26 season. They stated “The naming initiative helps the media and the public communicate about the impact of severe weather events more effectively.” Now in its eleventh year, the Met Office works with Met Eireann in Ireland and KNMI n the Netherlands to compile the list.

They continue “We name storms because it works. For Storm Eowyn in January, the UK’s most powerful windstorm for over a decade, past-event surveys suggest that 99% of people within the red warning area were aware of the warnings, and 89% of them took action.”

Saturday will be the last of the very hot days as the anticyclone edges away and we begin to come under the influence of a depression edging in from the Atlantic that will bring cooler, more moist air on a breeze from a southwesterly quadrant. This will see temperatures drop several degrees but likely to be just above average.

Puffins are known for their large, triangular-shaped beaks, which are brightly coloured during the breeding season.

The thermometer on Wednesday slowly climbed during the day to reach a peak of 28.5C at 17.21 being a significant 7.9C above my long-term average that made it the hottest day since 12th August 2024 (29.3C) with more heat to come over the next two days. Thankfully, to make sleeping more comfortable, the air temperature does drop away significantly overnight with a minimum of 11.0C at 05.18 early Thursday, which was just 0.8C above the average for June.

The new day on Thursday brought strong sunshine after sunrise that had lifted the temperature to 20.9C by 08.00. The slight relocation of the high pressure will see a drift of air from a southeasterly quarter dragging up hot air from the Continent today.

The persistent heat has slowly driven further and further into the ground that combined with warm nights has sent the ground temperature at a depth of 5cm to continue to rise with a reading of 22.3C at 08.00 this morning.

The anticyclone continues to very slowly edge eastwards with its centre now over the Netherlands, as a result the air circulating clockwise around its southern flank will feed the hot air from France and Iberia over the UK until Sunday, then there will be a significant change with more of an Atlantic influence and more modest maxima.

The high temperatures, not surprisingly, have resulted in the equivalent loss of rainfall due to evaporation from the ground and plant life rise significantly. The last two days has seen in excess of 5mm evaporate each day. The rainfall for June to date is just 31.5mm whilst the loss of equivalent rainfall now stands at 64.5mm.

The heatwave threshold for the Marlborough area is 27C. The maximum yesterday was above that figure, which will happen again today and also tomorrow. Thus we are technically experiencing a heatwave, which is described as three consecutive days with temperatures rising above the heatwave threshold. The original heatwave thresholds were based on the reference climate period of 1981-2010 and were intended to be flexible and revised in the light of climate change, therefore the heatwave thresholds were revised in 2022, using the most recent 1991-2020 climate averaging period, with the local threshold temperature rising from 26C to 27C. The review saw six counties move from 27C to 28C, one from 26C to 27C and one from 25C to 26C, the areas changed were in the south of the UK and the Midlands.

The image is of a puffling, a puffin chick.

The maximum of 24.3C on Tuesday was 3.7C above average making it the warmest day since 1st September. The UV level was again, not surprisingly, Very High with a value of 7.1. The overnight minimum under clear skies was 12.4C logged at 05.18 early Wednesday just after sunrise in Marlborough at 04.49.

There was glorious sunshine to start the new day on Wednesday with the light breeze coming from a northwesterly direction. The centre of the anticyclone is just off the northwest coast of Wales so light winds under the high pressure sitting over the UK due to little pressure gradient.

The high pressure will be the dominant feature well into next week. However, tomorrow it will ease a little further eastwards and northwards allowing the air stream to run around its southern flank bringing the extra heat from a hot Continent when the wind will veer into the southeast or south southeast. The heat will be maintained up to the weekend and into next week but by Sunday it will drop a couple of degrees from the peak temperatures.

Around 90% of the Atlantic puffin population are found in Europe with 80% in Iceland and Norway, the remaining 10% breed around Britain and Ireland.

The significant feature regarding Monday’s weather was the exceptionally high UV level, which during the bursts of strong sunshine was in the Very High category for two hours between 12.37 and 14.28, either side of midday, not surprisingly. However, the peak of 8.1 was at the very top end of the Very High category and the highest since 4th August 2024. The strong sunshine and light winds from the west, a maximum gust of just 10mph was recorded, saw the thermometer soar to a maximum of 24.1C at 16.49 being 3.5C above my long-term average. The intense solar activity produced a peak radiation of 1188 W/m2 at 12.53. The overnight minimum was 10.6C, just 0.4C above average, which was logged at 05.15 early Tuesday.

The start of Tuesday brought us bursts of sunshine, between variable cloud, that had lifted the temperature to 16.3C by 08.00. Today will see the cloud cover varying as a weak weather front passes southwards across our area.

The anticyclone now extends from the eastern Atlantic across to Germany with its centre just off the coast of Brittany. As we are now close to the centre of the high pressure the winds will continue light and from the west.

Later on Wednesday and into Thursday the high pressure will relocate a little to the east and elongate northwards that will then bring an air stream around its southern flank, originating from southern France and Iberia, which will mean the temperatures will increase over the next few days.

Puffins are about 20cm tall and breed in large colonies, such as the one on Skomer Island, Pembrokeshire. They breed in large colours on coastal cliffs or offshore islands.

The breeze from the west and variable sunshine on Sunday, especially in the morning, limited the rise in temperature to a maximum of 22.1C at 14.13, which was 1.5C above average and almost identical to the high on Saturday. The anticyclone has moved much closer to the UK with the pressure rising 8mb since Saturday. The low of 13.0C was logged just before midnight at 23.59 when the minimum is usually much later, towards dawn. This low was 3.7C above average.

Monday began with variable sunshine and bursts of sunshine that saw the thermometer climb to 17.2C by 08.00.

The high pressure has now extended over the UK and towards the Continent and is likely to dominate our weather for the rest of the this week that will see temperatures climbing over the next few days. The barometric pressure at 08.00 read 1029.2mb, which was the highest since the end of December. The slight relocation of the high will see the breeze continue to come from the west today. The centre of the anticyclone is in the western approaches to the English Chanel so being almost under the centre of the high the wind will be light today.

The warmer days and nights have seen the heat slowly penetrate further into the ground. The temperature at a depth of 5cm has risen steadily with 15.3C, 17.2C, 17.9C, 18.4C, 17.3C and then 19.2C today over the past six days and will continue to rise as the week progresses. The temperature of 19.2C at 08.00 made it the highest since the 12th August 2024.