The Lembeh Strait is a year-round diving destination — there is no bad time to visit, but understanding the seasonal patterns will help you plan the trip that best matches your goals, whether that’s flat-calm conditions for macro photography, peak critter activity, or avoiding the crowds.
Best Time to Dive the Lembeh Strait
Lembeh diving is good every month of the year. Water temperatures stay between 26–29°C year-round, and the protected nature of the strait means that even during windier periods, dive conditions are rarely seriously affected. Visibility in the Lembeh Strait typically runs 5–15 metres — lower than open-ocean reefs, but more than enough for the close-focus macro and critter diving the strait is famous for.
January – June: Calm Season
The first half of the year brings more rainfall but significantly less wind, which means flatter seas, easier boat rides, and generally excellent surface conditions. This is widely considered the best time to dive Lembeh for underwater photographers — calmer water means less silt movement and better visibility on many sites. Critter activity is consistently high throughout this period, with good sightings of frogfish, rhinopias, mimic octopus, and nudibranchs. Blackwater diving is particularly productive during the wetter months when plankton levels are higher.
July – December: Dry Season
The second half of the year is drier and windier. Surface chop can make the boat ride to some sites a little livelier, but conditions underwater remain excellent. This period brings some of the best critter diversity of the year — flamboyant cuttlefish, dragonets, ghost pipefish, and juvenile fish of all kinds are commonly encountered. The drier months also tend to have slightly better topside conditions for resort life — more sunshine, lower humidity, and beautiful sunsets over the strait from the bar.
Peak Season
NAD-Lembeh runs dedicated Blackwater Week events during peak season, when nightly blackwater dives are offered to all guests. If blackwater diving is a priority, check our rates and packages page for scheduled event dates.
Current Weather at NAD-Lembeh
The widget below shows current and forecast weather for the Lembeh area:
The above reflects general regional weather for the Bitung/Lembeh area. For more precise data, we have our own onsite weather station — the microclimate on Lembeh Island is generally a little cooler and receives slightly less rainfall than the Bitung readings suggest:
NAD-Lembeh Onsite Weather Station — Weather Underground
Water Conditions at a Glance
Water temperature: 26–29°C year-round (wetsuit or 3mm shorty recommended)
Visibility: 5–15 metres typical (macro diving — visibility is less critical than on reef dives)
Current: Generally mild in the strait; can be stronger at channel entry/exit points
Depth range: Most muck diving sites 5–25 metres