July will be remembered for hot, often humid, weather and thunderstorms, and it was the second warmest July on record here with an average temperature of 18.6C – a degree or so above normal but still half a degree below last year’s record-breaking July. The maximum temperature we recorded was 30.2C on the 24th, but that too was beaten by last year’s high of 31.2C. It was really just the second half of the month that was hot – the first week of July was relatively cool, and it was only towards the end of the second week that the warm weather got going.
There was a good deal of unstable weather throughout the month, with some very localised downpours. On 8 June, for example, a lunchtime thunderstorm at Weston-super-Mare, 10 miles north of this station, produced 25mm of rain in an hour while we basked in sunshine. On the same day Bournemouth was flooded by heavy rain and funnel clouds were seen in the Bristol Channel, but our total rainfall for the day was just 0.6mm.
By the middle of July we were under the influence of warm, humid air from the south. It was uncomfortably hot and sticky, with reports of thunder over much of the country. We got our turn on 19 July, starting with a thunderstorm at 0530 that brought us 9.2mm in an hour. During the day a column of thunderstorms just to our east moved steadily northwards but, although we could see the towering clouds and hear distant thunder for most of the day, there was no further significant rain until the evening.
At 1927 a very lively storm that had tracked across Dartmoor and Quantock arrived here and produced 10.6mm of rain in just 20 minutes, including 7.6mm in six minutes – one of the heaviest rainfall rates we have recorded. That deluge brought the total for the day to 22mm, more than half the month’s total of 42mm. This was the last recorded rain of the month.
By the next day the humidity had dropped appreciably, making the heat more comfortable. The following week was warm and sunny with a gentle north-easterly breeze. The north-easterly airflow was significant because it blocked the formation of a sea breeze which often keeps our temperatures in check, and from 23rd-26th July we saw daily maximum readings in the high 20s. A year-to-date high of 30.2C was recorded late on the 24th.
For the last few days of July the breeze was from the south-west, temperatures moderated and there was increasing cloud as we saw a switch to Atlantic weather systems. On the 31st there were a few drops of rain, though nothing measurable. So ended a warm and lively month.
The warmth of July has brought the average temperature so far this summer to 17.5C. If that figure is maintained during August, this could be our warmest summer since the station was set up.