What months have the roughest seas for Lombok to Sumbawa whale shark tours?

The roughest seas for travel between Lombok and Sumbawa generally occur during the Indonesian wet season, which runs from November through March. During these months, the region experiences more frequent rain, stronger winds, and choppier ferry crossings. The sea state in Saleh Bay itself can also be more unsettled during this period, although the early morning encounter window still often offers manageable conditions.

January and February tend to be the most unpredictable months, with monsoon-related weather systems occasionally bringing heavy rain and stronger swells to the Lombok Strait and the waters around Sumbawa. The ferry crossing, which is part of the 5 to 7 hour journey each way, can feel more turbulent during this season. That said, tours do operate year-round, and the team has experience managing wet-season logistics. Many days in the wet season are still perfectly fine for the trip.

If you are particularly sensitive to rough water or seasickness, the dry season from April to October offers the smoothest conditions and the most reliable experience. June through September is the peak window for calm seas and strong whale shark encounters. However, even in the wet season, the team will cancel or reschedule if conditions become genuinely dangerous — they never operate the tour in unsafe sea states regardless of the calendar month.