According to the Swiss Office temperatures (SAFT) is a water temperature of 19 ° C and higher, generally recognized as reasonable swimming and bathing temperature. This (alternative) fact has also led to the name of the app "19 degrees". The app shows on a map the water temperatures of Swiss lakes and rivers. Temperatures of below 19 ° blue (= cold) are identified and those of 19 ° and higher green (= generally acceptable).