Hai'an's climate is characterized by mild winters and warm summers. Spring arrives in late February with temperatures gradually warming up, reaching an average of 17°C in March. Summer months are hot and humid, with July being the warmest month, though exact temperature figures were not provided. Autumn brings a gentle decline in temperature, with September averaging around 24°C. Winter is relatively cool and dry, with December's low temperatures ranging from 4 to 12°C.