I just spent a week in Seram, Indonesia. It's an island just north of Darwin, Australia, pretty close to the equator. I've been to Indo a few times in the last 30 years and I remember diving off South Sulawesi (Bulukumba?). Major thermocline. I was shocked ! Maybe 5-6 Degrees Centigrade (28 down to 22?) I experienced the same thing on the north side of Seram a couple days ago. I don't think a 3 mm with a hood would have been enough wetsuit.
Anyway, I'm here working and regret not bringing a gun and gear. It's almost virgin territory. I only saw a couple small boats in a week. I went free diving three times right off the hatchery site. The drop off was only 200 feet off shore or so. Had to use a rock for weight and had some useless scuba, full foot fins. But I was getting down to maybe 60 feet and lying on the bottom. SHIT! 50-70 lb humphead parrot fish, 10-50 lb napolean wrasse (protected species) some nice snappers, one of which even El Marco would have been proud of me getting in arm's length ....and a 40 lb or so Spanish mackerel came right up to me while sitting on the sand slope drop off at about 60 feet. It was actually acting a little aggressive.
Anyway, if I come back, I'm bringing gear. Lot of stinging pneumatocysts in the water here Need a full suit and hood....for warmth too.
I think the cold water is due to the Indonesian Through Flow. Too much to typing to describe it, so please Google it. At about 1 degree south of the equator, this phenomenon seems to cool the water down and keeps the coral healthy. No sign of beaching.
Alright my brothers....hope to get some fish when I get back home to Belize in a couple weeks.