The thermometer on Wednesday slowly climbed during the day to reach a peak of 28.5C at 17.21 being a significant 7.9C above my long-term average that made it the hottest day since 12th August 2024 (29.3C) with more heat to come over the next two days. Thankfully, to make sleeping more comfortable, the air temperature does drop away significantly overnight with a minimum of 11.0C at 05.18 early Thursday, which was just 0.8C above the average for June.
The new day on Thursday brought strong sunshine after sunrise that had lifted the temperature to 20.9C by 08.00. The slight relocation of the high pressure will see a drift of air from a southeasterly quarter dragging up hot air from the Continent today.
The persistent heat has slowly driven further and further into the ground that combined with warm nights has sent the ground temperature at a depth of 5cm to continue to rise with a reading of 22.3C at 08.00 this morning.
The anticyclone continues to very slowly edge eastwards with its centre now over the Netherlands, as a result the air circulating clockwise around its southern flank will feed the hot air from France and Iberia over the UK until Sunday, then there will be a significant change with more of an Atlantic influence and more modest maxima.
The high temperatures, not surprisingly, have resulted in the equivalent loss of rainfall due to evaporation from the ground and plant life rise significantly. The last two days has seen in excess of 5mm evaporate each day. The rainfall for June to date is just 31.5mm whilst the loss of equivalent rainfall now stands at 64.5mm.
The heatwave threshold for the Marlborough area is 27C. The maximum yesterday was above that figure, which will happen again today and also tomorrow. Thus we are technically experiencing a heatwave, which is described as three consecutive days with temperatures rising above the heatwave threshold. The original heatwave thresholds were based on the reference climate period of 1981-2010 and were intended to be flexible and revised in the light of climate change, therefore the heatwave thresholds were revised in 2022, using the most recent 1991-2020 climate averaging period, with the local threshold temperature rising from 26C to 27C. The review saw six counties move from 27C to 28C, one from 26C to 27C and one from 25C to 26C, the areas changed were in the south of the UK and the Midlands.
The image is of a puffling, a puffin chick.