Water temperature of the Java Sea in september Where to swim in the Java Sea in september 2025?

Several countries border the seaside of the Java Sea, including: Bali, Indonesia, Java and Sumatra. We measure the water temperature daily in these countries and archive it in order to calculate monthly averages, like those of the month of september.

The seasonal average for the water temperature in the month of september is between 80°F and 84°F. The lowest sea temperature measured this month is 77°F and the highest is 87°F.

The sea temperature map of the Java Sea in september

The map below presents a monthly average of the water temperature of the Java Sea for the month of september for several coastal cities. You can zoom and move around on the map. By clicking on the markers, you can see sea temperature details by city in september.