Koszalin's winters are cold and snowy, with temperatures often dropping below -20°C in January and February. Spring arrives in March, bringing moderate temperatures that gradually warm up throughout the month, with some days reaching up to 21°C. Summer is mild, with July being the warmest month, averaging around 20°C, but rarely exceeding 31°C. Autumn is characterized by a decrease in temperature, with September and October experiencing average highs around 14°C and 9°C respectively, before dropping again into winter. The coldest months are December and January, while June and July are the warmest.