New evidence based on recent satellite data is presented to provide a rare opportunity in quantifying the long‐speculated contribution of tropical cyclones to enhance ocean primary production. In July 2000, moderate cyclone Kai‐Tak passed over the South China Sea (SCS). During its short 3‐day stay, Kai‐Tak triggered an average 30‐fold increase in surface chlorophyll‐a concentration. The estimated carbon fixation resulting from this event alone is 0.8 Mt, or 2–4% of SCS's annual new production. Given an average of 14 cyclones passing over the SCS annually, we suggest the long‐neglected contribution of tropical cyclones to SCS's annual new production may be as much as 20–30%.