Situated within favorable conditions, the system quickly reached tropical storm intensity before strengthening further to typhoon status a day after formation.

Intensification continued until Billie reached its peak intensity on July 14 east of Taiwan with maximum sustained winds of 165 km/h (103 mph) and a minimum barometric pressure of 970 mbar (hPa; 28.64 inHg).

Beginning on July 9, the Joint Typhoon Warning Center (JTWC) began dispatching aircraft reconnaissance to investigate an area of thunderstorms between Yap State and Koror that had potential to develop into a tropical cyclone.

[1] Tracking westward,[2] there were few signs of organization or intensification until July 12, when recon found a closed atmospheric circulation within the disturbance, signifying that a tropical depression had developed; JTWC bulletins and warnings commenced accordingly.

[3] Now tracking steadily towards the northwest,[1] the typhoon reached its peak intensity at 1200 UTC the next day with maximum sustained winds of 165 km/h (103 mph) according to the JTWC and a minimum barometric pressure assessed by the Japan Meteorological Agency (JMA) at 970 mbar (hPa; 28.64 inHg).

[1][2] Over the Korean peninsula, Billie began to intake cold air from a polar front, enabling the system to transition into an extratropical cyclone by 1800 UTC that day.

[7] The Japanese freighter Bansei Maru was grounded on a reef off of Ishigaki Island due to the rough surf and winds caused by the passing typhoon, necessitating a rescue operation by three United States Navy ships.

[9] Approximately one-third of Taipei was inundated by floodwaters, and hospital patients were forced to evacuate to Okinawa after a Military Assistance Advisory Group compound was impacted by the heavy rains.

[11] Storms accompanying Billie and its remnants brought heavy rains and strong winds to South Korea, knocking out police telephone lines in Busan.