A day with zero crossing is defined as a day with temperature both below 0 °C and above 0 °C measured two metres above the ground.
Zero crossings are very common in central Sweden with an average of 100-120 days per year. The least number of zero crossings occurs in south of Sweden, around the lake of Vänern and along the coast.
Generally the number of zero crossings is large during spring, but they are almost as frequent during both autumn and winter. Throughout the summer, however, this phenomenon is rare in most parts of the country.
Zero crossings in the future
According to SMHI’s latest climate scenarios, where zero crossings have specifically been studied, the results show a decrease in number throughout the country during autumn and spring. In the wintertime the number of days with zero crossings will also decrease in the south, while there will be an increase in central and northern Sweden.