Wednesday 24th June
After a cloudy start on Tuesday, which was a relief until around 09.30, the sun began to beat down mercilessly all day that saw my June record of 32.2C set in 2017 beaten as the thermometer reached a maximum of 33.6C late in the afternoon at 18.19, which was a significant 12.8C above my long-term average. There was little relief overnight as the temperature only very slowly dropped to a minimum of 17.9C at 04.26, just before sunrise in Marlborough at 04.51, which was 7.7C above average.
Wednesday arrived with the sun beating down very strongly after it had risen above the eastern horizon, that had lifted the temperature to exactly 25.0C by 08.00. The anticyclone is centred over Ireland and will slowly extend its area eastwards and over the near Continent tomorrow, but still dragging in the extreme heat from a very hot Continent.
The maximum of 33.6C exceeds my previous record by a significant margin of 1C, of 32.2C set on 21st June 2017. The previous highs were 31.4C in 2020 and 31.3C set in both 2022 and 2025. This new record is likely to be beaten again today and possibly tomorrow as we reach the zenith of the intense and extreme heat.
P.S. yesterday’s maximum of 33.6C was surpassed at 15.58 with a reading of 33.7C and still rising.
The relentless intense sunshine has seen the ground slowly absorb the heat, rising daily, with my ground thermometer set at a depth of 5cm, read at 08.00 every morning, register, 21.2C, 22.9C, 23.3C and 25.6C respectively over the past four nights.
The extreme heat and strong sunshine, combined with a modest breeze, has seen much of the recent rainfall lost into the atmosphere. The past three days has seen the equivalent daily rainfall of 5.1mm, 5.4mm and 5.5mm respectively, evaporate from plant life and the ground. The monthly rainfall stands at 66.8mm whist we have lost 80.9mm due to evaporation.
We did not have a ‘tropical’ night last night, which is when the minimum does not drop below 20C. However, it is certain to occur during Wednesday and Thursday nights, so very hot and humid nights ahead until Friday into Saturday bringing some relief when the minimum drops a few degrees, but still above average.
What is a heat health alert?
The UKHSA Heat Health Alert system is an England only service, designed to highlight the potential impacts of heat on human health, particularly for vulnerable groups. Issued in collaboration with health agencies, it focuses on the cumulative effects of heat rather than just peak daytime temperatures.
Alerts are graded at yellow, amber and red levels, allowing a broader range of potential impacts to be communicated. This means an alert can be issued even when temperatures are not exceptionally high, but conditions are still likely to pose risks.
For example, a prolonged spell of moderately high temperatures can lead to increased health impacts over time. Similarly, very warm nights can reduce the body’s ability to recover, raising the potential for heat-related illness. In such situations, a Heat Health Alert may be issued without a corresponding Met Office extreme heat warning.
Compton Acres near Poole, where my pictures were taken a number of years ago, consist of five themed sub-gardens; an Italian garden, a Japanese garden and a less formal woodland garden called the “Wooded Valle”.