The northwestern and northeastern monsoons are not so strong and irregular when Borneo blocks the winds. This made sailing on this water safe and free from gales as well. The influence of sea and land breezes, either those coming from Sulawesi or from Kalimantan Island were also dominant here. Land breeze from Sulawesi blows during the southeastern monsoon of July–September and the sea breeze moves during the northwestern monsoon of October–April, while the land breeze from Kalimantan blows during the northwestern monsoon and the sea breeze in the southeastern monsoon. This enabled a trade connection between Makassar and the ports along the
west coast of Sulawesi, such as Pare-pare, Suppa, Majene and Kaili and the trading centers along the south-east coast of Kalimantan such as Banjarmasin, Samarinda and Bulungan On the south coast of Kalimantan, the southeastern monsoon blows from May to September, accompanied by a good deal of rain. During the northwestern monsoon (from October to April) westerly winds prevail, with continual rain and frequent storms. On these waters, the currents generally follow the direction of the prevailing winds