The cold sum of a winter or month is obtained by adding up all the amounts of negative daily mean temperatures (temperatures below 0 ° C). The opposite is the heat sum .
This statistical value is often used in connection with the freezing behavior of lakes .
In order to judge the severity of a winter, a sum of all negative daily mean temperatures from November to March is formed . The result provides the following statement:
Summe < 100 = sehr milder Winter
Summe 100–200 = normaler Winter
Summe 201–300 = mäßig strenger Winter
Summe 301–400 = strenger Winter
Summe > 400 = sehr strenger Winter