Shiojiri's winters are cold and variable, with temperatures often below freezing in January and December, but occasionally rising into the mid-teens. As spring approaches, temperatures gradually warm up, with March marking a significant increase towards double digits on average. The summer months of June to August bring consistently hot temperatures, with highs frequently reaching above 30°C. Autumn is characterized by a cooling trend, with September experiencing mild temperatures before dropping back down into the single digits in November.