The past twenty-four hours have been dominated by the disturbed weather associated with low pressure systems arriving from the Atlantic bringing their weather fronts with them. The rain on Tuesday eventually petered out in the afternoon but left occasional showers. The persistent cloud meant a cool day with the thermometer not climbing above 18.9C at 14.34, during the brief bright interludes in the afternoon, being almost exactly average for early September at -0.1C. There was intermittent light rain in the early hours of Wednesday and heavier arriving just before 06.00 that in total amounted to 13.7mm, which took the monthly total to 21.9mm in two days.
The past night was very mild under the cloud cover, not dropping below 14.2C logged in the very early hours of Wednesday at 01.51 being a significant 5.5C above my long-term average. This variation between the day and night temperatures is referred to as the diurnal range and on this occasion produced a difference of only 4.7C. Last month there were many days when the diurnal range was in excess of 10C.
The start to Wednesday revealed 8/8ths cloud cover with the clouds scudding across the sky under a brisk southwesterly wind having veered from the southeast on Tuesday. The two low pressure systems dominating our weather will combine and continue the unsettled weather, with rain and brisk breezes as the day progresses, whilst the depressions join and become centred over the Scottish Borders.
There are multiple weather fronts crossing our region today with a line of heavy showers approaching Cornwall at 09.00 and likely heading our way later in the morning.
Another media headline has splashed that some weather charts indicate the mercury could climb back up to 30C this month, with temperatures set to rise across southern England from Monday, 8th September. However, the Met Office has cautioned Brits against dusting off their suncream and beach gear just yet, suggesting that this month’s forecast is more likely to feature moderate conditions, falling short of heatwave levels.
The selection of autumnal images from Stourhead continue.
August 2025 Review
The new month continued with the modest strength north-westerly, travelling around northern periphery of the ridge of high pressure with variable cloud. The 3rd brought a very warm day as the wind had backed into the west with a maximum of 24.4C.
In winter we often hear about wind chill when the temperature is low and there is a strong wind blowing that makes it feel colder outside than indicated on the thermometer, referred to as the THW factor using data of temperature, humidity and wind strength. The opposite has occurred over the past few months when we have had very high temperatures, referred to as the Heat Index (THSW) that uses the additional data of solar strength that makes it feel hotter outside than indicated on a thermometer.
Taking the data from the 2nd as an example, although the maximum on the thermometer read 22.3C at its peak at 14.30 outside it was computed to feel more like 28.3C. That was one hour after 13.30, peak time under BST, when the solar read 849W/m2.
The 4th was notable for the arrival of the fifth Named Storm of the season being Storm Floris that paid a one-day visit, predominantly to Scotland. However, being on the periphery we only experienced gusty winds up 26 mph and modest rainfall in the afternoon of 1.4mm. The centre pf the deep depression had a minimum pressure of 976mb whilst at 08.00 locally it was 10167mb. The considerable pressure differential cased the storm force winds in the north but no gales over Southern England, just very windy.
Temperatures began to climb again from the 10th under a large area of high pressure that heralded the arrival of the fourth Heatwave this year. The peak temperature was logged on the 12th when the thermometer reached 32.8C being 10.7C above my long-term average.
There followed a quieter period in the third week with maxima below average due to a brisk breeze coming around the north of the high pressure then arriving from the northeast.
The Bank Holiday once again saw the temperature very briefly soar again to reach 27.5C, some 5.4C above average.
A significant change in the weather pattern was heralded on the 26th as the remains of ex-hurricane Erin was absorbed into a deep depression in the North Atlantic. This resulted in the wind veering into the southwest with an Atlantic influence on our weather and the first precipitation after fourteen consecutive dry days. The rain spots at 06.30 followed by very brief, light drizzle amounted to 0.2mm.
The cooler and more moist air also meant a drop in temperatures that for the last few days in the month were below the average.
There was substantial and welcome rainfall on the 28th that began to quench the thirst of parched ground, much to the relief of gardeners. It was mainly intermittent rain with the longest period in the evening that eventually totalled 16.8mm being the wettest day since 23rd February.
There were 25 dry days in August equalling those recorded in April. The remaining days, when rain did fall, produced a total of 31.1mm, which was 47% of my 41-year record or minus 34.4mm. The wettest day was on the 28th with 16.8mm. Set against this limited rainfall was the loss of equivalent rainfall through evaporation from ground sources and plant life that totalled 94.0mm.
It was another very warm month with the average temperature 2.1C above almost entirely due to the very hot days as there were fourteen days when the overnight minimum was below average. The hottest day (12th) reached 32.8C when the coolest day (20th) only reached 18.3C, which was 3.9C below average.
The warmest night was recorded on the 13th with a minimum of 16.4C whilst a very cool night was logged in the early hours of the 22nd with a low of just 4.5C, being a significant 6.5C below my long-term average.
Summer 2025.
The three metrological months of Summer, being June, July and August, produced a mean temperature of 18.29C, being 1.8C above my long-term average.
The rainfall for summer totalled 116.2mm, which was 67mm below my 41-year average.
