When using the Köppen climate classification, Hanoi is categorized as having a monsoon-influenced humid subtropical climate (Köppen Cwa) with plentiful precipitation like other places in Northern Vietnam. The city experiences the typical climate of Northern Vietnam, with four distinct seasons. Summer, from May to September, is characterized by hot and humid weather with abundant rainfall, and few dry days. Hot, dry conditions caused by westerly winds during summer are rare. From October to November comprise the fall season, characterized by a decrease in temperature and precipitation, this time in the year mostly are warm and mild. Winters, from December to February, are characterized as being cool by the northeast monsoon, giving Hanoi a dry winter and large amount of sunshine. Spring, from March until the end of April, Hanoi is usually characterized with large amounts of drizzle and little sunshine due to the strong activity of the southeast monsoon blowing moisture from the sea inland. The city is usually cloudy and foggy in this time, averaging only 1.5 hours of sunshine per day in February and March. The city occasionally experiences cold waves from the Northeast originating from the Siberian High. Hanoi is the only capital of Southeast Asia with a subtropical climate.
When using the Köppen climate classification Hanoi is categorized as having a monsoon-influenced humid subtropical climate (Köppen Cwa) with plentiful precipitation like other places in Northern Vietnam The city experiences the typical climate of Northern Vietnam with four distinct seasons Summer from May to September is characterized by hot and humid weather with abundant rainfall and few dry days Hot dry conditions caused by westerly winds during summer are rare From October to November comprise the fall season characterized by a decrease in temperature and precipitation this time in the year mostly are warm and mild Winters from December to February are characterized as being cool by the northeast monsoon giving Hanoi a dry winter and large amount of sunshine Spring from March until the end of April Hanoi is usually characterized with large amounts of drizzle and little sunshine due to the strong activity of the southeast monsoon blowing moisture from the sea inland The city is usually cloudy and foggy in this time averaging only 15 hours of sunshine per day in February and March The city occasionally experiences cold waves from the Northeast originating from the Siberian High Hanoi is the only capital of Southeast Asia with a subtropical climate