When IS The Best Time To Dive Lembeh?
Posted on Jun 01, 2008 by bruce_mooreI often get prospective guests asking about the weather and sea conditions. The big question is "When is the best time to dive Lembeh?". In the past I could give a reasonably dependable breakdown of our conditions over the course of any given year. But over the past few years a discernable shift has occurred in that pattern, just as conditions around the world have grown more irregular. Some blame the broad specter of global warming, extreme weather change, natural weather cycles exacerbated by deforestation and pollution, George Bush or the Tooth Fairy. Whatever is the cause, all bets seem to be off, so-to-speak.
The Dependable Good Old Days
January usually brought lower visibility and until June conditions would be mixed with variable visibility and water temperatures with some strong winds blowing sporadically in April as a precursor to the June monsoon startup. The critters would be less as well, especially until April or so, but many divers enjoyed the quieter months because they received more attention as resorts weren't so busy. Guides would often find really cool super-wee critters (shrimps / nudis) as they worked harder to keep guests happy. April would be an excellent month for mimic octopus with flamboyant cuttlefish starting to appear here and there. May would bring bluering octopus mating season. And every time a cold upwelling blasted through the strait, another cycle of nudibranch and ghost pipefish appearances would initiate.
Then in early-mid June the monsoon winds blowing from the south-east would crank up, building through July and August before abruptly ceasing in early September. These winds would start up around 10 am every morning and slow down again at sundown, but more importantly they would drag up cold, plankton-rich waters from deep off shore into the strait. The diving conditions would be less than pleasant at times owing to chilly water (24-26 degrees C) and goopy plankton bringing down visibility to 4-6 meters at times, especially in August. Cotton candy-like algae would grow on the sand substrate of the muck sites, making critters harder to find. Guides would routinely lose their guests within minutes of entry owing to the gloomy conditions. Photographers would finish taking photos of a critter, raise their head to look about and not know where the rest of their group had gone. Guests would be shivering from their dive, but then would get really cold back on the boat, getting blasted by the winds even before boat started to move back towards their resort of origin.
But these same conditions brought on a banquet of critters. Nudibranchs, ghost pipefish and octopus would be in their highest concentrations of the year. Almost all the sites would be "hot". Shivering divers would be loathe to surface since there was so much to see. Even guests who were separated from their buddies would find plenty to see. In literary terms, it was the best of times; it was the worst of times.
Then in early September, within days of the winds abating, the visibility would increase to 25 meters or more, the water temperature would climb to 28 degrees C or so and all the critters were still there, but now much easier to find in calm and clear conditions. Normally July-August are traditional peak months, but over a few years, as word circulated, I noticed the Lembeh busy season shift to September-October and for good reason. The diving was unbelievably awesome.
All that would change in early November though, as the water would warm further to 30 degrees C or more, which drove many critters deeper. Also, currents would bring in jellyfish, flotsam (plastic) washed down into the ocean owing to the start of the rainy season and tree stumps along with other large pieces of wood would appear, possibly from Kalimantan (Borneo). Kambahu Bay was often filled with this stuff, forcing divers to surface carefully, pushing aside all manner of impediments just trying to get back to their boat. Then conditions would stabilize in December, when Christmas brought more divers who more often than not had great dives.
And Now?
And now it seems to be rather different. Over the past few SE monsoon seasons the wind has been strong, but seems to lack the vehemence of previous campaigns. The water temperature hasn't plummeted to such chilling depths in late July as it used to. The visibility hasn't been so dependably miserable through August. The "cotton candy algae" has been less and less every year to the point of being barely there. I recall seeing up to 8 filamented ghost pipefish in a single dive at Larry's Crack and easily finding them amongst the algae at Jahir and Hairball as well, but now every year there are less and less. We see them during any month as a matter of luck rather than season. The numbers of critters found in July through October are still higher than the rest of the year, but it's not so dramatically different than in years past. November has been offering stunning dives with plenty to see without jellyfish and stumps for a few years now. The early parts of the rainy season still result in more plastic and trash visible, but the Bitung city government has been improving its waste management capabilities, so I predict this problem to continue to decrease in the future as environmental awareness initiatives and education increases.
Special critters such as harlequin shrimp, halimeda ghost pipefish, flamboyant cuttlefish and Rhinopias are spotted at any time, so in a way it is more difficult to say when is the best time to dive Lembeh.
In 2006, the monsoon winds did not abate early in September, but lasted until the end of the month. In 2007 they continued to blast us until the end of October. And the rainy season kicked off the very next day with daily massive downpours, completely skipping the calm / high visibility / critter-rich period we expected. But even if the weather patterns are impossible to predict, the diving has been steadily good, regardless of the weather. Since we opened the only period of low visibility was a few days over Christmas, but by the end of the year it was ~20 meters, making up for the earlier soupiness. Indonesia as a whole has been experiencing the waviest storm season in memory, but in sheltered Lembeh the winter winds only affect the upper half of the island-side sites, so for the most part guests haven't been affected.
So how will the weather be for the rest of 2008? Your guess is as good as mine.
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