A meteorologist who developed the climate classification system that bears his name. He was born in St Petersburg, Russia, of German parents, studied at the universities of Heidelberg and Leipzig, and during 1872–3 worked in the Russian meteorological service. In 1875 he moved to Hamburg, Germany, where he headed a new division of the Deutsche Seewarte, formed to issue weather forecasts for the land and sea areas of northern Germany. He was able to devote himself entirely to research from 1879. He died in Graz, Austria.