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) that were previously uncompetitive, now grew extensively. The citizens of Hamburg were driven to make use of articles of German origin much more freely than before, as many of them were cheaper than corresponding foreign articles which were now weighted with a Customs duty. As predicted, the new conditions favoured the development of manufactures in Hamburg itself. With the free port, Hamburg became the leading port in continental Europe and the world's fourth largest after New York, London and Liverpool. This continued the increase of trade prior to the accession, which in 1873- 1887 grew by 44.2%. Nevertheless, outside the