Thanks to zkxs from our discord we can share some information about trade winds
The trade winds affect the wind as follows[]
The wind direction changes randomly periodically, and if you're inside a given trade wind area the wind's direction is also adjusted towards the trade wind's direction with a 25% weighting. The result of this is that while there will be some jitter, on average the winds will follow the relevant trade wind.
Regarding the edges of the map
The trade winds continue off the edges of the map forever. This means if you needed to go super far east off the edge of the map for some reason, you can just extrapolate the areas in my image out.
The actual trade wind regions[]
North trade wind[]
North of 33° latitude. Blows from 243.4° (WSW)
West trade wind[]
West of -2° longitude. Blows from 225° (SW)
South trade wind[]
South of 32° latitude. Blows from 63.4° (ENE)
Note[]
If regions overlap, the priority is North > West > South
A visual overlay of the prevailing Trade Winds over the Ocean map.
Note the dead zone east of -2° and between 32° and 33° latitude. There the wind's direction is random. Trade winds affect island clusters as well as the open ocean.
It is better on average to stay above 33° for a Journey from Gold Rock City to the Emerald Region - thanks Odoty