A typhoon is a tropical revolving storm (TRS) — an intense, rotating low-pressure weather system with sustained winds of at least 64 knots — that forms specifically over the northwestern Pacific Ocean.
Same Phenomenon, Different Names by Region
- Typhoon — northwestern Pacific Ocean (a region seeing frequent, often severe TRS activity, particularly relevant to vessels trading through Southeast Asia and East Asia)
- Hurricane — Atlantic Ocean, northeastern Pacific
- Cyclone — Indian Ocean, South Pacific
There is no meteorological difference between these — only the ocean basin where the storm forms determines which name applies.
Why the Northwest Pacific Sees Frequent Typhoons
Warm sea surface temperatures across a large area of open ocean, combined with favorable atmospheric conditions, make the northwestern Pacific one of the most active TRS basins in the world, with typhoon season typically running from roughly June through November, peaking around August-September.
Danger to Shipping
Vessels trading through this region need active typhoon tracking and avoidance planning during the relevant season, applying the same avoidance principles (dangerous vs navigable semicircle) that apply to any TRS.
Exam Relevance
Typhoon formation, seasonal patterns for the Pacific region, and TRS avoidance procedures are core Meteorology topics in deck officer competency exams.