Hejian experiences cold winters with temperatures often dropping below -20°C in January, gradually warming up in February and March as the average high rises above freezing. Spring arrives in April, bringing mild temperatures ranging from 3-26°C, while May is characterized by warm days with averages around 21°C. Summer months of June to August are hot and humid, with July being the warmest month, but still relatively cool compared to other parts of China. Autumn brings a slight cooling trend in September, followed by crisp temperatures in October, before winter's chill returns in November and December.