Author: Eric Gilbert

Yesterday was the hottest day this year in Marlborough when the thermometer soared to 31.9C just after 4.30pm. Last year the hottest July day occurred on the 1st with a maximum of 32.6C although the record was set on 19th July 2006 with a peak temperature of 35.1C.

Also memorable yesterday was the continuous strong (100watts/m2.) sunshine that totalled 15.79 hours. This is the highest number of hours recorded this year and beats the previous high set on 30th June last year.

Broken cloud moved across during the evening that reduced the radiation of the extreme heat from the ground into the atmosphere that produced a very warm night with a minimum of 20.4C. just after 5.30am. This is a record for my station that started operating in 1984, the previous high being set on 20th July 2006. By 8.00 am today the thermometer had risen a little to 21.2C.

Due to the minimal rainfall and higher temperatures over the last four days the soil temperature at a depth of 5cm rose to 23.1C at 8.00am

This month we have had very little precipitation; the total for the first 19 days is 10.4mm, which is a fraction of the mean for July of 61.0mm. Not surprisingly, the total for the equivalent rainfall lost through evaporation from plant life, water surfaces and the ground is 55mm giving a deficit so far this month of 45mm.

The thermometer soared yesterday as a result of the hot air from the continent reaching a peak of 28.8C, the hottest day since 1st July 2015. There was very little cooling breeze, a maximum gust of just 9mph and 9.55 hours of strong sunshine, the sunniest day since the end of May.
With a minimum overnight of 14.4C, the temperature had recovered to 20.4C at 08.00 and the soil temperature at a depth of 5cm now the highest this season at 21.1C.

With the sun breaking through in the afternoon the thermometer rose to a maximum of 24.7C yesterday. Clear skies overnight resulted in fog forming from the moist air and falling temperature, which restricted visibility to 100m. The overnight minimum was 13.7C. The fog started to thin very slowly after 7am as the sun struggled to break through the fog.

A touch of summer yesterday when the thermometer rose to a maximum of 24.2C, the hottest day for a month. Although there were only 0.75 hours of strong sunshine, the UV level rose to ‘very high’ just after 1pm, the highest level this year. The very mild and moist southwesterly air, with cloud cover overnight, meant that the minimum was 15.9C, which is 5C above the mean for July and the second warmest night this month.