By Philip Eden
Pressure remained persistently low over the British Isles until the 20th, but this was followed (curiously, as in both March and May) by almost a week of hot and sunny weather, at least over England and Wales. Unsettled weather returned at the end of the month.
Mean maximum temperature during July ranged from 21.6°C at St James's Park (London) to 13.0°C at Fair Isle (between Orkney and Shetland), while mean minimum temperature varied between 14.3°C at Olympic Park South (London) and 8.1°C at Dalwhinnie (Inverness-shire). Daytime temperatures were typically 1.0-2.5 degC below the long-term average in most parts of the country, whereas night-time temperatures were 0.0-1.0 degC below. The Central England Temperature (CET) of 15.5°C was 1.2 degC below the mean for 1981-2010 - the lowest in July only since 2011, though five of the last six Julys have been cooler than average. In the last 100 years 29 Julys were colder, 65 were warmer, while six had the same overall temperature.
The highest maximum at a standard site (i.e excluding rooftop and mountain sites) in the UK was 30.7°C at St James's Park (London) on the afternoon of the 25th, while the lowest minimum was 0.8°C at Tulloch Bridge (Lochaber) early on the 31st. The lowest daytime maximum was 10.3°C at Aviemore (Inverness-shire) on the 7th, while the warmest night was that of 23rd/24th with a minimum of 19.1°C at Llanfairfechan (Caernarfon).
Rainfall averaged over England and Wales during July was 114mm which is 171 per cent of the average for the standard reference period 1981-2010. It was the wettest July only for three years; however, in the last 100 years just ten Julys were wetter while 90 were drier. The equivalent figures for Scotland were 103mm and 145 per cent of the normal amount, and for Northern Ireland 81mm and 114 per cent. Monthly totals at routinely-available sites varied between 210mm at Spadeadam Forest (Cumbria) and 35mm at Kirkwall (Orkney).
Sunshine averaged over England and Wales during July was 165 hours which is a mere 81 per cent of the 1981-2010 mean, making this the dullest July (alongside 2010) since 1998. In the last 100 years, 24 Julys were duller while 76 were sunnier. The equivalent figures for Scotland were 111 hours and 69 per cent, and for Northern Ireland 148 hours and 91 per cent. Largest total in the UK was 220 hours at Jersey airport (Channel Islands) and the smallest was just 60 hours at Eskdalemuir (Dumfriesshire). Other low aggregates were 69 hours at Dyce (Aberdeenshire) and 70 hours at Kinlochewe (Wester Ross).
By Philip Eden