Climate indices are usually derived from measured variables such as temperature, precipitation or sunshine duration. How precisely an index is defined depends on the specific application. However, there are numerous climate indices that have become established worldwide. They were selected by an international team of experts to gather data about climate change with the help of indices. Since the indices are consistently defined globally, this allows the comparison of data across national borders and different climate regions. These indices include, for example, the number of hot days, frost days, and wet days.
More detailed information is available on the following indices: