By Roger Brugge
Now that we are half-way through August, the nights are getting longer and a Bank Holiday approaches, I thought it would be a good moment to take a preliminary look back on the summer of 2015 in Reading. UK news stories about the weather this summer seem to have been focused either on cold and wet conditions in parts of Scotland, or on torrential and damaging thunderstorms – so how does the summer of 2015 in Reading compare to past years?
A look at the wind directions at 0900 GMT reveals more of a south-westerly component this year, when compared to the average – Figure 1. This flow direction reflects the lower than normal pressure reported in western parts of the British Isles for much of the summer; e.g. especially in July and August at Stornoway.
Figure 1. The 0900 GMT wind direction during summer 2015 (black line) compared to climatology (red shading) at Reading – all averages refer to the standard 30 year period of 1981-2010. The winds are plotted as percentages of all possible days.
Perhaps (maybe fortuitously for us this year) this tendency towards a flow from the south-west has helped to keep the very hot continental conditions away from our shores (except for the close of June/start of July). On 5 July the temperature in Kitzingen am Main in Germany climbed to 40.3 °C – the highest recorded in Germany since nationwide measurements started in 1881 (Deutscher Wetterdienst noted that many Germans found July unpleasant). In Vienna, by 10 August there had been 10 days this summer reaching 35 °C – compared to only 14 in the previous ten years and never more than 5 days in any previous summer on record. In Holland the June-July heatwave lasted six days with 2 July seeing 38.2 °C in Maastricht, while 39.7 °C was recorded in Paris. In Reading, after a record 30.6 °C at 0900 GMT on 1 July, the maximum temperature reached 33.6 °C later in the day; hot, but this ranked only fifth in the list of hottest July days on record.
There was no thunder in Reading as this heatwave ended; indeed, Reading seems to have missed out on much of the thundery activity that occurred in the in the UK this summer. Even as recently as 13 August when fire crews in Kent and Sussex were called out to houses struck by lightning during severe thunderstorms, and flooding forced play to be suspended at the women’s test match in Canterbury, just 10.1 mm of rain fell in the Observatory raingauge – without accompanying thunder in Reading. In fact, only one day with thunder has been noted this summer in Reading – the average is 4.3 days in summer and there were 11 thunder days last year, following a spell of seven years with relatively little thundery activity.
In summary then, by 0900 GMT on Friday 14 August, in Reading this summer the average temperature had been about 0.2 degC below average, rainfall was running at a 16 mm deficit (of the total fall of 97 mm, 59 mm fell on just three days – one of these being the wettest July day for eight years) and the amount of sunshine was 12 per cent above normal. So not too bad a summer, albeit a cool one in those south-westerlies!
Interestingly, spring 2015 was quite a sunny season – and the total sunshine so far this month according to our Campbell-Stokes instrument is 1251 hours. This is 194 hours more than would be expected so far this year, and no month since November 2014 has been duller than average. The year to date has also been dry – the 293 mm of precipitation received so far is barely 83 per cent of the normal for the year to mid-August.
The Bank Holiday is yet to come but, as readers of One hundred years of Reading weather will be aware, only about two years in five remain totally dry in Reading during that weekend in August …