Which German climatologist helped create the Köppen-Geiger climate map?

Rudolf Geiger was the German climatologist who helped develop the Köppen-Geiger climate classification and its global climate map.

Geiger was born in Erlangen in 1894 and became a meteorologist and climatologist. His work extended the climate classification created by Wladimir Köppen, whose system grouped climates using temperature and precipitation patterns. The resulting Köppen-Geiger framework became one of the most widely used ways to map the world's climate zones.

Geiger was part of a notable scientific family: his father was the Indologist Wilhelm Geiger, and his brother was the physicist Hans Geiger, known for work connected with the Geiger counter. Geiger himself focused on climatology rather than nuclear physics.

The name “Köppen-Geiger” can cause confusion because Köppen created the original classification, while Geiger later revised and advanced it. Alexander von Humboldt and Carl Ritter were major figures in geography, and Alfred Wegener developed continental-drift theory, but none is the canonical answer to this question.