Upwellings (General)
Think they call the one running parallel to Taiwan the hei-chao or black tide. Forming/embedded in it are upwellings - which bring cold water from the deep up to the surface. Have been swimming a few times where the water was significantly colder - even in summer.
As for Wikipedia - yeah it's a great concept but unfortunately became a target for United Front Work Dept type networks. Their censorship of anything remotely suggesting a lab-leak was every bit as ferocious as mainstream media. But still good for non-political topics.
On your point, i always wondered why southern hemisphere climate doesn't necessarily co-relate with equidistant northern hemisphere climate. For example there will be snow in Europe/US during winter but not in Australia at the same distance from the equator.