May ended where it began with dry, warm weather that saw the temperature rise to a peak of 24.1C at 13.12. after a very sunny morning, variable cloud drifted over during the afternoon that limited any further rise. The residual sub-tropical air meant a mild night although a little cooler than previous nights with a minimum of 11.2C at 04.41, just before the sun rose in Marlborough at 04.56. This low was 1.0C above my long-term average for June.
Sunday had a splendid start under glorious sunshine with the thermometer having risen to 14.4C by 08.00. During the night two cold fronts passed our way so today will not be quite so warm but likely to continue the dry trend although the rain radar this morning showed shower activity just north of Bristol and Exmoor at 08.20.
Tomorrow will see a transient ridge of high pressure assert itself to bring a dry day with sunny periods.
May 2025 Review
The month began with very warm days as the breeze came from a warm southeasterly direction with a maximum of 28.1C on the 1st, being a significant 10.8C above my long-term average.
By the 3rd a high-pressure system had begun to develop and become the dominant feature for the following week continuing the dry period. Sadly, it meant a persistent northeasterly breeze, strong at times, with variable cloud that depressed the daytime maxima. On both the 4th and 5th the thermometer struggled to reach 13.9C being 3.4C below average.
This period also brought very chilly nights that saw the temperature fall very close to freezing with a minimum of 0.7C in the early hours of the 6th. As a gardener I was very anxious for the tender plants that I had perhaps set out in the garden too early after the previous very warm spell, but thankfully no air frost occurred so no damage was caused but it probably slowed their development.
The other significant feature of the weather was the continuation of the dry period until just 0.6mm and 0.5mm fell on 11th and 13th. During the latter-day thunderstorms developed and tracked north-eastwards from Kent to South Wales, just missing Marlborough. The same occurred on the previous day, but just to the north of our region.
The high pressure to the north then built, extending its influence across the country whilst at the same time elbowing the recent depression back into the Atlantic, whence it came, where it filled and disappeared.
The fine sunny weather returned, albeit with chilly nights, into the following week. The thermometer dropped to a surprisingly low minimum of 1.9C in the early hours of the 23rd.
Numerous thunderstorms passed us by on the 21st with minimal rainfall, that appeared to deflect around Marlborough to the west and east. One noisy thunderstorm passed overhead at 17.10 on the 21st but minimal precipitation fell from it, just 3.1mm.
It was all change on the 24th that saw the end of the dominant high-pressure system to the north that had brought persistent northeasterlies. A depression arrived, centred between Ireland and Iceland, that saw the first breeze from a Westerly quadrant for over a month, but alas for gardeners, little rainfall overnight of the 23rd.
Some useful precipitation fell on the 27th then 9mm was recorded on the 28th making that the wettest day of the month.
The last week was initially dominated by unsettled weather principally due to a succession of weather fronts arriving from the Atlantic, such a contrast to much of the month. However, the last three days saw the high pressure to the south of the UK edge closer with a flow of sub-tropical air that lifted maxima well above average.
The total rainfall for May amounted to just 23.9mm being only 40% of my 41-year average or 36.5mm below. The total rainfall covering the period of January to May was 259mm against the 41-year average of 338mm. Thus, this was only 79mm below the 41-year average due to the very wet first two months of 2025.
The average temperature for May was 1.2C above my long-term average, principally due to the numerous very warm days and no overnight air frosts, although it got close with a minimum of 0.7C in the early hours of the 6th.
Thunder was heard on the 21st on several occasions, the first at 12.45, then 15.10 and for a short period at 17.10 when it was overhead.