What are the patterns of typhoon activity in September? Why do multiple typhoons frequently affect China in succession during this month?
TyphoonSays·防御问答 · The Typhoon Season · 更新 at 2026-09-20
Why is typhoon activity so active in September?
As we enter September, many people notice that typhoons remain a frequent feature in weather forecasts, with "consecutive typhoons" impacting China one after another. This is not accidental but determined by the combined effects of atmospheric circulation and oceanic thermal conditions. Although the Start of Autumn (Liqiu) has passed, sea surface temperatures in the Northwest Pacific often reach their annual peak during this period, providing ample "fuel" for typhoon formation and intensification. Meanwhile, changes in the position and intensity of the subtropical high create steering flows that favor typhoons approaching China's coastal areas. Consequently, September has historically been the second peak season for typhoon activity, with generation numbers and landfall frequencies second only to August, meaning the situation for typhoon defense remains severe.
The Power and Characteristics of "Autumn Typhoons"
Meteorologically, typhoons formed from June to August are referred to as "summer typhoons," while those formed from September to November are called "autumn typhoons." Compared to summer typhoons, autumn typhoons tend to have more complex tracks, greater intensity, and higher destructive potential. This is because cold air masses become more active in autumn; when a typhoon encounters southward-moving cold air, it can trigger heavier rainfall and stronger winds. Additionally, autumn typhoons sometimes move slowly or linger near the coast, prolonging the duration of wind and rain impacts, which easily leads to urban waterlogging, flash floods, and geological disasters. According to the National Standard for Tropical Cyclone Grades issued by the China Meteorological Administration (CMA), once the maximum sustained wind speed near the center reaches Force 12 or above, it is classified as a typhoon, warranting high alert.
Scientific Defense and Response Recommendations
Facing the possibility of consecutive typhoon impacts, the public should discard the lucky mindset that "typhoon season is over" and maintain routine preparedness:
- Monitor Warning Signals: Closely follow the blue, yellow, orange, or red typhoon warning signals issued by meteorological authorities. Note that specific criteria for school suspensions and work stoppages may vary by location; please refer to the latest notifications from local governments and education departments.
- Clear High-Altitude Hazards: Inspect and secure items prone to falling, such as balcony flower pots, outdoor air conditioning units, and awnings, to prevent them from being blown down and causing injury during strong winds.
- Stockpile Emergency Supplies: It is advisable to keep flashlights, power banks, drinking water, and a small amount of non-perishable food at home to cope with potential short-term disruptions to water and electricity supplies.
- Avoid Unnecessary Risks: During typhoon impacts, avoid going to seaside areas, mountains, or low-lying zones, and do not linger near water bodies to watch the waves.
Typhoon paths are highly variable and difficult to predict, especially for autumn typhoons, which are influenced by the interaction of multiple weather systems, leading to greater uncertainty in their tracks. Keeping informed and obtaining the latest forecasts in a timely manner is key to ensuring personal safety. Real-time typhoon tracks can be queried on TyphoonSays (taifengshuo.com)
This article is original educational content from TyphoonSays. Please refer to the latest official announcements from local governments for policy standards.