of Bergheim. Administrative structures Heidelberg is a unitary authority within the Regierungsbezirk Karlsruhe. The Rhein-Neckar-Kreis rural district surrounds it and has its seat in the town, although the town is not a part of the district. Heidelberg is a part of the Rhine-Neckar Metropolitan Region, often referred to as the Rhein-Neckar Triangle. This region consists of the southern part of the State of Hessen, the southern part of the State of Rhineland-Palatinate (Vorderpfalz), the administrative districts of Mannheim and Heidelberg, and the municipalities of the Rhein-Neckar-Kreis. The Rhein-Neckar Triangle became a European metropolitan area in 2005. Heidelberg consists of 15 districts distributed in six sectors of the town. In the central area are Altstadt (the Old Town), Bergheim and Weststadt; in the north, Neuenheim and Handschuhsheim; in the east, Ziegelhausen and Schlierbach; in the south, Südstadt, Rohrbach, Emmertsgrund, and Boxberg; in the southwest, Kirchheim; in the west, Pfaffengrund, Wieblingen, and a new district, named Bahnstadt, is built on land in Weststadt and Wieblingen. The new district will have approximately 5,000–6,000 residents and employment for 7,000. Further, new residential space for 10,000–15,000 residents was made available in Patrick Henry Village following the departure of the US Armed Forces. Neighbouring communes The following towns and communes border the city of Heidelberg, beginning in the west and in a clockwise direction: Edingen-Neckarhausen, Dossenheim, Schriesheim, Wilhelmsfeld, Schönau, Neckargemünd, Bammental, Gaiberg, Leimen, Sandhausen, Oftersheim, Plankstadt, Eppelheim (all part of the Rhein-Neckar-Kreis) and Mannheim. Climate Heidelberg has a humid subtropical climate (Köppen climate classification Cfa), defined by the protected valley between the Pfälzerwald and the Odenwald. The almost year round warm temperatures are usually determined by Atlantic air masses in the winter and increased influence from the western Mediterranean in summer. This results in drier summers and wetter, cloudier winters on average. In contrast to the nearby Upper Rhine Plain, Heidelberg's position in the valley leads to more frequent easterly winds than average. The hillsides of the Odenwald favour clouding and precipitation. Spring starts early and is one of the warmest in Europe besides the Mediterranean Coast. Especially April has a tendency to be also very dry, while the rising temperatures in May can create some thunderstorms with higher precipitation levels. Nights start cold and usually stay fresh throughout almost the whole spring, while day temperatures can already become hot from April on (30°C/86°F and higher). Summers are long, hot and mostly dry. Day temperatures are