Budapest later, with the help of the Russian Empire. 1867 was the year of Reconciliation that brought about the birth of Austria-Hungary. This made Budapest the twin capital of a dual monarchy. It was this compromise which opened the second great phase of development in the history of Budapest, lasting until World War I. In 1849 the Chain Bridge linking Buda with Pest was opened as the first permanent bridge across the Danube and in 1873 Buda and Pest were officially merged with the third part, Óbuda (Old Buda), thus creating the new metropolis of Budapest. The dynamic Pest grew into
Budapest night. Budapest's long summer – lasting from May until mid-September – is warm or very warm. Sudden heavy showers also occur, particularly in May and June. The autumn in Budapest (mid-September until late October) is characterised by little rain and long sunny days with moderate temperatures. Temperatures often turn abruptly colder in late October. Spring and Autumn are generally mild. Mean annual precipitation in Budapest is around . On average, there are 84 days with precipitation and 1988 hours of sunshine (of a possible 4383) each year. The city lies on the boundary between Zone 6 and Zone 7 in