The weather in in August 2013

Severe thunderstorms in warm, moist air, but otherwise friendly and dry

Offenbach, 29 August 2013 – The start of August 2013 saw high atmospheric pressure over eastern and low atmospheric pressure over western Europe, which brought warm and moist subtropical air to Germany. Some regions experienced violent thunderstorms, often ac- companied by heavy rain, stormy wind and large hailstones. After this, the high atmospheric pressure over the North Atlantic was dominant. Successive high pressure areas broke away and moved towards central and northern Europe. The prevailing weather in Germany was now often pleasant and with more agreeable temperature levels. This weather was only occasionally interrupted by low pressure areas. Overall, it was a pleasantly warm, dry and sunny August, as the initial analysis by the Deutscher Wetterdienst (DWD) of data from its around 2,000 weather stations shows.

Initially extremely hot, but then a pleasant month

At 18.0 degrees Celsius (°C), the average temperature in August exceeded the long-term figure, as recorded by the international reference values for 1961 to 1990, by 1.5 degrees. Looking at the comparative period 1981 to 2010, the difference was +0.5 degrees. A southerly airflow at the start of August brought the third heat wave of this summer. Consequently, the maximum temperature on 2 August was almost as high as the temperature on 27 July. The highest tem- perature was recorded in Geilenkirchen to the north of , where the mercury rose to 38.4°C. Even on Borkum and Norderney, the temperature rose to 34°C. From 7 August on- wards, somewhat cooler air flows reached Germany and temperatures fell to more pleasant levels. An autumn chill was often present at night. -Brüderwiese in the Mountains recorded a minimum temperature of only 1.2°C.

Heavy thunderstorms in some regions of the south, very dry across the north

August 2013 was much too dry, as was July. With around 55 litres per square metre (l/m2), pre- cipitation was just 72 per cent of the long-term average of 77 l/m2. Distribution of in Germany in the course of this month was generally determined by the paths of thunderstorms. These downpours occurred in very sultry air, particularly between 4 and 9 August and on 19 August, especially in southern and central Germany. Lightning strokes, heavy rain, storms and hailstones, some of which were larger than 12 cm, caused considerable damage in many places. Marienberg- in the reported the highest daily rainfall of

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74.4 l/m² on 6 August. Overall, precipitation fell directly on the northern edge of the from the Allgäu to the Berchtesgadener Land, with up to 190 l/m² being recorded. It was rare for thunderstorms to reach the north and north-east, where often less than 20 l/m² and, in some places, as little as 10 l/m² was recorded.

Lots of sun – particularly in north-east and south-west Germany

In a normal year, the month of August has 197 hours of sunshine so, at 220 hours, August 2013 was 20 per cent sunnier than usual. This month, the extreme north-east and the extreme south- west enjoyed the most sunshine. The least sunshine was recorded in a broad band from the northern part of the Mountains passing through the and the Thuringian to the Ore Mountains.

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