|MadSci Network: Earth Sciences|
That, of course, would vary with the weather and the time of year. But you should not be too surprised when I tell you that it would be found in an equatorial region, under direct sunlight, and with shallow and fairly still waters, possibly trapped behind a reef or sandbar. One region that does have beaches with very high water temperatures quite consistently is the Indonesian Archipelago. I believe, for example, that in Torres Strait, between the Northern tip of Australia and Papua Niugini, some of the coastal and island beaches get water temperatures into the 40s (celsius) at times, and even the ocean temperature away from the beach gets well into the 30s. I do not know whether that is the highest, but it would go close. I am not even quite sure how you would define the highest beach temperatures. For example there is a lava beach at the foot of Kilauea in Hawaii where the ocean water is boiling and rising in clouds of steam! (because molten lava from a continuing eruption is entering the ocean underneath the lava shelf) Perhaps that would be the record? You can access information about sea surface temperatures from the NOAA website. I found a map giving SSTs for September 2000 in the Mexican Gulf/Caribbean region, which shows temperature readings around 30°C and slightly above near the islands of Jamaica and Hispanola. SSTs are defined in terms of a sample taken at 1 metre depth, and for the purposes of this map were averages of several readings taken at different times, and over a 1 degree square, that is, about a 60 mile square. Beach water temperatures at 4 p.m. on a sunny afternoon would be warmer than these values. The Caribbean is not unlike the Indonesian region in having a lot of islands and a lot of shallow water. It is not as extensive, and not as close to the equator.
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