Author: Eric Gilbert

Friday saw the last of the hot days, for the time being, with a maximum of 28.0C (+5.7C), the day marked by much more cloud and only 3.9 hours of strong sunshine.

The wind, now from a southerly direction, became gusty during the late afternoon as the low pressure approached.

Overnight the barometric pressure fell to its lowest this month, just before 5am with a reading of 1000.2MB, as a cold front passed through the area. This change in weather brought cooler Oceanic air from the Atlantic. The wind began to gust strongly just before 3am today with a peak gust of 27mph at 05.16 but still from the the south, the strongest gust since 26th May, bringing a short, brief shower that gave us just 1mm of rainfall.

Saturday arrived with broken cloud but the sun broke through by 07.30 raising the minimum temperature of 13.8C (+2.1C) to 14.9C at 08.00.

Update at 10.50: brief squall at 10.45 with wind gusting to 28mph and a few large rain drops but no quantity. A roll of thunder was heard at 10.58. The current storm passed to the west of us with storms last night passing to the east. This pattern has been observed often over the years as if the topography of the area deflects storms around Marlborough, unlike weather fronts.

Update at 16.15: gust of 35mph at 15.54, which was the highest speed since 1st March (39mph). A maximum temperature of 20.3C was recorded at 15.18, which was almost 8C down on the Friday maximum and 10C down on the Thursday maximum.

Update at 21.15: real rain at last with heavy rain for almost twenty minutes.

Thursday saw the thermometer soar during the morning before a build up of cloud after midday halted the rise at 13.35 with a maximum of 30.4C, which was 8.1C above the 34-year average. The thermometer hovered around 30C for most of the afternoon. The previous record of 34.5C was set in July 2006.

The afternoon of Thursday saw strong gusts of wind from the south as the air became less stable with localised storms moving north to the west and east of Marlborough.

A very mild night followed with minimum of 14.9C, which was 3.1C above average.

Friday dawned with strong sunshine, after the clearance of cloud near the horizon, that boosted the temperature to 20.3C at 08.00.

A change in the weather is approaching as the barometric pressure has been dropping and at 08.00 is at its lowest this month.

Update at 16.00: maximum temperature of 28.0C at 15.04, down 2C on the Thursday peak but 5.3C above average. Less heat due to increased levels of cloud and thus reduced sunshine.

Wednesday brought a day with 11.6 hours of sunshine and Very High UV that lifted the temperature slightly higher than recorded on Tuesday with a maximum of 27.8C, which was 5.5C above the 34-year July average.

July to date:
Average maximum mean temperature: +5C
Rainfall: 4.9mm (average is 60.9mm)
Evaporation: equal to 108mm of rainfall
Sunshine: 220 hours

The average strong sunshine for July, over the past four years when this instrument was installed, is 109 hours. This instrument is triggered when the sun’s strength reaches 100w/sq.m.

Thursday arrived with, initially, broken cloud and occasional glimpses of strong sun that lifted the minimum of 11.7C, exactly average for July, to 16.8C at 08.00.

Update at 11.00: temperature just reached 28.0C, already beating highs of last two days, which usually occur mid to late afternoon. Mean maximum is 22.25C

11.00: 28.0C
11.30: 28.6C
12.00: 28.8C
12.30: 29.2C
13.00: 29.7C
13.00: 30.3C
13.35: 30.4C – the hottest day this month/ year
14.00: 30.2C
14.30: 29.6C
16.00: 29.9C

These temperatures are from instruments well up my garden on the outskirts of Marlborough. Instruments within an urban environment where there are numerous buildings, much paved concrete and tarmac surfaces also not in the shade from direct sunshine or shaded from solar energy, will indicate higher temperatures.

Tuesday brought another hot day with 9.42 hours of strong sunshine and a maximum of 27.7C at 15.34, almost 3C down on Monday’s peak but still 5.4C above average.

No day in July has seen the maximum fall below the 34-year July average of 22.25C.

My station is positioned on the outskirts of Marlborough, well up the garden and the furtherest away from any building and paved area. Therefore any instrument in the town closer to buildings of next to paved/tarmac areas that soak up the heat will give a higher daily reading. Also, although thermometers might be in the shade, professional instruments are all shaded from solar radiation to get as accurate an ambient temperature as possible and as close to Meteorological standards that can be obtained.

Overnight the minimum of 13.8C was recorded at 05.54, just after the sun rose. A short while later variable cloud obscured the sun but well before 8am the sun was coming through strongly and by 08.00 the temperature had risen to 18.0C.

Update at 17.18: maximum temperature of 27.8C reached at 17.15 with humidity exceptionally low currently reading just 33% in very light south westerly air of 5mph.

Monday saw the thermometer soar to 30.3C making it the hottest day since 21st June 2017 and 8C above the 34-year average.

The total hours of strong sunshine was the highest for a week with 11.25 hours.

There followed a much cooler night with a minimum of 12.3C, just above average.

By 08.00 on Tuesday the thermometer had already risen to 19.5C under the effect of one hour of intermittent strong sunshine.

The Meteorological Office class a day as dry if any precipitation is less than 1mm. Since 30th May we have had 49 dry days out of the 54 period.

June rainfall of 5.3mm BUT evaporation equivalent to 110mm of rainfall
July rainfall of 4.9mm BUT evaporation equivalent to 95mm of rainfall

Update at 17.20: maximum lower today at 27.7C, being 2.6C down on Monday’s peak due to variable cloud and reduced hours of strong sunshine. However, the peak today was still 5.4C above the 34-year July average.