of and sits at elevation ranging from above sea level by the Neckar river to on Bernhartshöhe hill – something rather unique in large German cities. The most prominent elevated locales in Stuttgart are the Birkenkopf () on the edge of the Stuttgart basin, the Württemberg () rising above the Neckar valley, and the Grüner Heiner () at the northeast end of the city. Stuttgart is one of 14 regional centers in Baden-Württemberg and is naturally the primary centre of the Stuttgart Region, making it the administrative centre for a region of containing a total of 2.76 million people as of December 2014. In addition, Stuttgart serves as a Mittelzentrum for Esslingen District cities Leinfelden-Echterdingen and Filderstadt as well as Ditzingen, Gerlingen, and Korntal-Münchingen in Ludwigsburg District. Stuttgart is also chief of the three centres Stuttgart Metropolitan Region, an area of containing 5.3 million persons. Climate Stuttgart experiences an oceanic climate (Köppen: Cfb), just like the British Isles and Northern France, but it is very extreme at times. As a result of the urban heat island caused by the dense development of the city, inside its "Cauldron" average temperatures in the summer months regularly beat from June to August and come very near in September. In the winter temperatures are quite mild, with daily means never sinking below even in the coldest months (January and February). In spite of the heat, there is no dry season and the city receives frequent but moderate precipitation year-round. Annually, the city receives average of rain (German average national annual rainfall is ). On average, Stuttgart enjoys 1,807 hours of sunshine per year and an average annual temperature of . Typically during summer months, the nearby hills, Swabian Alb mountains, and Black Forest, Schurwald, and Swabian-Franconian Forest act as a shield from harsh weather but the city can be subject to thunderstorms, whereas in the winter periods snow may last for several days. Winters last from December to March. The coldest month is January with an average temperature of . Snow cover tends to last no longer than a few days although it has been known to last several weeks at a time as recently as 2010. The summers are warm with an average temperature of in the hottest months of July and August. Summers last from May until September. Though it is a rare occurrence in Stuttgart, the city sometimes receives damaging hailstorms,