You are using SMHI (The Meteorological service) definition of winter which is > the daily average temperature is at most 0 degrees Celsius at least 5 days in

You are using SMHI (The Meteorological service) definition of winter which is > the daily average temperature is at most 0 degrees Celsius at least 5 days in a row This doesn't work for the international reader, in many countries the temperatures in the winter never goes below zero