The brisk westerly on Saturday pegged back the temperature to a peak of 21.3C, which was 1.6C below the 39-year average, but it was dry and the UV level in the Very High category.
The overnight minimum of 9.8C was also below average -2.1C.
Sunday revealed a sunny start to the new day but the brisk westerly still continued.
June 2023 Review
June broke the 39-year temperature record due to persistent warmth for much of the month.
The weather for the first week was dominated by a blocking high pressure that had been resident over the north Atlantic for several weeks. The north-easterly wind, gusting to 20mph or more, persisted throughout this period.
There were 24 continuously dry days by the 7th, higher than the previous dry spell in September 2002 by three days.
On the 8th the first signs of a change in our weather pattern were noted with the barometric pressure the lowest since 11th May as the anticyclone eased away and Storm Oscar moved northwards.
On the 9/10th a plume of very warm and moist air arrived from the near continent, pushed forward by Storm Oscar to the south. Useful amounts of rain for the gardens arrived on the 10th and 11th with 9.3mm and 5.5mm respectively, the first in June.
The temperature steadily rose to a maximum of 29.8C at 15.02, which was 9.6C above the average, before cloud began to arrive from the southeast and the first light drops of rain were observed. This was the hottest day since the heatwave in August 2022 when 33.5C was noted on the 13th.
A classic Line of Convergence was seen on the radar screens at that time as the hot, moist air from the Continent, brought on a south-westerly air stream, met the colder, drier air from the northeast, that had been plaguing our area for the last three weeks. The warm, moist air, being lighter, rose above the colder air mass and rapidly condensed forming storm cells that brought the first rain drops at 15.10. Further cells developed in a line to the southeast and moved north-westwards across our area, due to the wind veering from northeast to southeast, with heavy rain from 15.40. A total of nine thunderclaps were heard during this period.
The showers, sometimes very heavy, produced 9.3mm of very welcome rainfall for the gardens and filled three of my 220 litre water buts. The rain eased and ceased at 17.05 and the sun began to reappear, weakly at first.
During the storm period the air temperature fell precisely 10C from 29.9C to 19.9C. The thermometer began to rise again at 17.05.
The warm air mass meant a very mild night with the thermometer not sinking below 15.7C, which was 5.7C above the average.
The following day brought another 5.5mm of precipitation.
There was then a significant change in our weather with a very dry, hot and sunny period from the 12th to the 16th, which was classed as a heatwave. The heatwave threshold for Wiltshire is 27C. The maxima for this period were 27.8C, 28.6C, 27.6C, 27.1C and 27.8C. respectively, so a local heatwave was declared after the third day when a maximum above 27C was recorded.
It was all change again on the 17th when a narrow band of rain arrived from the southwest producing a light shower amounting to 0.2mm and much lower temperatures.
The 18th started fine and dry but late afternoon the cloud began to well up and the first storm cell arrived with rain at 18.50. The rain radar indicated that this storm cell would pass over the area within a few minutes but watching the radar the storm cell lingered and built for nearly two hours producing 15.1mm of rainfall. This considerable rainfall was very welcome by gardeners as it fell in modest strength but did not damage plants. No thunder or lightening was observed.
A further major rainfall occurred in the early hours of the 20th, triggering the automatic rain gauge at 04.30, when 26.6mm was recorded and at 06.00 was recorded falling at the rate of 110mm/hour. So intense was the rain it knocked over the tops of some of my broad beans. This was the wettest day since 19th December 2022.
All my daily rainfall totals are taken using the standard 5inch Meteorological Office copper rain gauge. The automatic rain gauge is very useful for live rainfall logging but can be affected by wind gusts whereas the copper gauge is sited in grass with the top 30cm above ground level.
Another hot spell was logged from the 22nd to 25th. It was the second hottest day of the month on the 24th with a maximum of 28.7C and the highest UV level in June, which was at the very top of the ‘Very High’ category and the highest since 15th August 2021.
The end of the month was noted for the roller coaster of weather fronts that crossed the UK daily, with warm front followed by cold front then warm front again. As a result, each day brought a different air mass varying from warm, moist air to cooler, fresher air. The warm front that crossed the area on the 27th gave a very warm night in the early hours of the 28th when the thermometer did not drop below 16.4C. This was 6.3C above the average and the warmest night since 3rd August 2022 (18.1C).
By contrast, the north-westerly air stream, originating from Greenland and Iceland, meant a very cool night during the early hours of the 30th when the thermometer fell to 6.3C being 3.4C below average and the coldest night since the 3rd (6.2C).
The average temperature for June was 24.13C. It was 2.46C above the 38-year average and the warmest June I have recorded since the station was set up in 1984. Further analysis reveals that the average June maximum was 3.55C above the 39-year average and the minimum +1.36C.
The total rainfall for June was 62.5C being exactly 9mm above the long-term average. However, set against that figure was the high rate of evaporation due to the strong sunshine and drying winds. The equivalent loss of rainfall due to evaporation from ground sources and plant life was 105.2mm with the greatest daily rate of 5.2mm on the 13th.
The rainfall for the period January to June was 471mm being 82mm above the long-term average.
The average barometric pressure of 1018.6mb was 2mb above the long-term average.