Geography and urban development of Dresden temperatures are almost the same as those in cities in southwest Germany; on average 10.2°C per year. In hot summers, Dresden is between the hot Lusatia and the milder Ore Mountains. Both regions are characterised by strong winters: temperatures of −20°C are not impossible in Dresden. The driest months are February and March, with precipitation of 40 mm. Spring months have often been arid in the last couple of years (with less than 10 mm of precipitation). The most precipitation falls in July and August, at 60 mm per month. Due to its location on the banks of the Elbe
Accession of Hamburg to the German Customs Union (Zollverein) by Hamburg. Thus Hamburg consumers had lower prices than consumers within the union. The German imperial constitution of 1871 brought no change in the legal situation of Hamburg and Bremen. Article 34 (and related provisions) went into the new constitution. After Hamburg had agreed to the constitution of the North German Federation, negotiations were held between November 1867 and March 1868 on the size of the free area. It was agreed that this would cover the Hamburg urban area, but not the outlying areas, including Ritzebuttel, Bergedorf and the Vierland (which were a condominium with Lübeck until January 1868), Waldvörfer,