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What temperature threshold separates BWh and BWk climates?
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Köppen climate classification
The major climatic types are based on patterns of average precipitation, average temperature, and natural vegetation. This map depicts the world distribution of climate types based on the classification originally invented by Wladimir Köppen in 1900.
In the Köppen climate classification system, the temperature threshold that separates the h (warm) and k (cold) subtypes for arid climates is 18 °C.1
Specifically, for the desert climate subtypes:
* BWh: The average annual temperature is equal to or greater than 18 °C.1
* BWk: The average annual temperature is less than 18 °C.1