Karimunjawa tide times

Predictions: Open-Meteo Marine (MeteoFrance SMOC, 0.08° grid) — heights relative to MSL (not chart datum / LAT). Model-derived.

Model-derived from a global ocean grid. Useful indication; expect about ±45 minutes on average vs. a local harmonic gauge, individual stations vary widely. See /methodology for per-region detail. Not for navigation.

Conditions as of 11:00 local time. Refreshes daily.

Predictions: Open-Meteo Marine (MeteoFrance SMOC, 0.08° grid) — heights relative to MSL (not chart datum / LAT). Model-derived. · Not for navigation.

The angler tradition for major/minor fishing windows: major ≈3-hour windows around moon transit and opposition; minor ≈2-hour windows around moonrise and moonset. Times are Asia/Jakarta local. Folk tradition, not a scientific forecast.

Karimunjawa is an archipelago of 27 islands and islets in the Java Sea, roughly 90 km northwest of Semarang in Central Java. The group was designated a national marine park (Taman Nasional Karimunjawa) in 1999 and covers approximately 111,625 hectares, the majority of which is marine area including coral reefs, seagrass beds, and mangrove systems. The main island, also called Karimunjawa, holds the village, ferry dock, and most accommodation. Tides in the Java Sea here are strongly diurnal to mixed diurnal — a markedly different character from the Indian Ocean south coast. BMKG data for the Karimunjawa area records a mean tidal range of approximately 0.6 m. The daily inequality is pronounced: on many days there is effectively one dominant high water and one dominant low water per 24 hours, with the secondary tides very small. The practical consequence for reef activities is that tidal exposure is predictable and mild — at low water the reef crests may be exposed by 0.3–0.5 m, but unlike macrotidal coasts, the reef is accessible for snorkelling and diving through much of the day. The reef system covers an area of roughly 7,100 hectares within the park. Coral health in the outer reef sections is better than the inner lagoon areas, which have experienced some pressure from boat anchor damage over the years. The park authority regulates dive and snorkel sites; mooring buoys are installed at the most sensitive sites to prevent anchoring. Water visibility on a calm day runs 15–25 m at the outer reef stations; the Java Sea is shallower than the Indian Ocean and more susceptible to suspended sediment after wind events. Access to Karimunjawa is by fast boat from Jepara (approximately 2 hours) or by the slower ASDP ferry. Crossings are weather-dependent — the Java Sea can become rough quickly under the north-westerly monsoon (December through February). The best season for sea conditions and visibility is April through October, when south-easterly winds keep the sea generally flat. BMKG (Badan Meteorologi, Klimatologi, dan Geofisika) is the authoritative source for tidal predictions in Indonesian waters. Open-Meteo Marine data shown here carries ±45 min / ±0.2–0.3 m uncertainty.