You probably saw a multi-colored climate map at least once in school. You might have pored over it, fascinated. Was Antarctica really a cold desert? And why was so much of Russia listed as tundra?

We introduce Version 2 of our widely used 1-km Köppen-Geiger climate classification maps for historical and future climate conditions. The historical maps (encompassing 1901–1930, 1931–1960, 1961–1990 ...