Friday 1st August
Thursday was notable for the frequent and heavy showers that passed over Marlborough on several occasions during daylight hours producing 9.3mm of welcome rainfall that has now filled all my five water buts. This was the wettest day since 26th February, also the wettest month since February, and took the monthly rainfall to 41.3mm set against my 41-year average of 59.8mm. It was significant that between the showers the sunshine was intense that produced the strongest peak solar energy of 1201W/m2 since the end of June. In addition, it was notable that the UV level rose to 7.3 at 11.52, not surprisingly, also at the time of the peak solar strength, being in the ‘Very High’ category, just before one of the heaviest showers arrived. As the sky cleared in the evening the temperature dropped away to reach a low of 11.0C at 05.25, just before the sunrise in Marlborough at 05.25.
Friday arrived with variable sunshine that had lifted the temperature to 13.2C by 08.00. A cooler and drier day is ahead.
The Azores High is showing signs of building back over the UK for the next couple of days that should result in drier conditions with longer spells of sunshine reappearing, especially on Saturday.
NEWS FLASH
Storm Floris has been named by the Met Office. This unseasonably disruptive system will bring strong winds and heavy rainfall across the northern half of the UK on Monday and early Tuesday.
July 2025 Review
The latter end of the June heatwave continued on the 1st that gave us a very hot day peaking at 30.1C with three more warm and sunny days following until the 5th.
The dominant Azores High had been begun to recede back into the Atlantic from whence it came on the 5th allowing a depression to the north, near Iceland, to take over our weather. There were a couple of very light and brief drizzle incidents during the morning of the 5th and 6th, with minimal rainfall, that soon evaporated.
Referring to the cycles of hot weather followed by cooler and changeable weather the UK has seen recently, Met Office meteorologist Aidan McGiven said: “During the past three weeks or so the UK has been through two cycles of what appears to be a repeating weather pattern.” “Now we’re in July that heat has been pushed aside as the High pressure has retreated to the southwest, back to the Azores. This semi-permanent high pressure that you get near the Azores, known as the Azores High, has been ebbing and flowing from the southwest through the last week, hence this repeating cycle.”
The Azores High is a semi-permanent area of high atmospheric pressure located over the eastern North Atlantic Ocean, typically near the Azores archipelago. It influences weather patterns across Europe as well as in North Africa, and parts of North America.
The Azores High began to extend over the UK on the 8th, initially the breeze was from the northwest as the airstream travelled clockwise around the western flank of the anticyclone before streaming around its northern edge and then down across the UK.
As the centre of the high relocated eastwards across the UK the breeze began to come from a southeasterly quadrant that allowed the heat to build combined with hot air pulled up from the Continent and produced our third heatwave of the year. The maximum reached in this heatwave was 32.9C on the 11th. The heat was intense that felt very uncomfortable when the maximum air movement, couldn’t be called a gust, was only in single figures and at times the anemometer was stationary.
The high pressure began to lose its control on the 16th allowing a depression to the northwest to edge closer that saw the wind direction change to west and then southwest that brought a warm, and moist airflow.
A disturbance, with numerous thunderstorms, developed over northern France on the 18th and drifted north over the UK overnight but, sadly for gardeners, once again the main rain band was just to the east of Marlborough, that gave us only 0.7mm. I again wonder if there is a geographical reason why in these shower situations the bands of rain, often drift predominantly to the east, and less extent, to the west of Southern England .
The Azores High began to exert its influence again on the 23rd with a ridge over the UK. Initially, the air travelled around its western flank then came around its northern edge with the wind from the direction, that took the edge of the warmth. However, by the 24th the ridge had edged southwards over the UK allowing the air to flow from the west, that combined with the barometric pressure continuing to build, resulted in the temperatures beginning to climb again.
The month ended with the Azores high edging westwards, just a little, that allowed several weather fronts to edge around its north periphery bringing showers on a north-westerly breeze. The 31st was the wettest day since 26th February with 9.3mm. This took the monthly total to 41.3mm being 69% of my 41-year average or minus 18.5mm. It was also the fifth successive month with below average rainfall. Analysing the year to date the rainfall for the period January to July gave us 338mm of precipitation when the 41-year average for those five months is 451mm.
July was another month with above average temperatures as the mean was 1.9C above my long-term average. Breaking that down the average maximum was +2.4C and the average minimum was +1.9C.