| Term: | Cold cap |
| Definition: | As defined by A. Supan (1879), a region of the earth within which the mean temperature of the warmest month is less than 10C. This limiting condition closely approximates the temperature at the arctic tree line, and was later adopted by W. Köppen (1918) as his boundary between the polar climates and tree climates. Supan also defined temperate belt and hot belt in his early form of climatic classification. |