The Celebes Sea has narrow deep channels to the Indian Ocean; it is filled mainly by western Pacific water masses. A tropical monsoon climate exists around the Sulu archipelago, with a dry winter (November–April) and a rainy summer (May–October).
How is narrow deep channels?
“Narrow channels” are easy to define: They are natural or dredged passages adjacent to shallow water, often marked with lateral (red and green) buoys and range markers. All vessels utilizing a channel must remain as close to its starboard edge as they can safely manage.