If you believe the paper by Ramanathan and Collins "Thermodynamic regulation of ocean warming by cirrus clouds deduced from observations of the 1987 El Ni?o" it's because of cirrus clouds.

http://www.nature.com/nature/journal/v35...

There are exceptions. For example, when lava flows into the ocean from Hawaiian volcanoes it reaches about 100 Deg C but admittedly that is a small exception but you did use the word never.

Anyway, there are a few reasons. The atmosphere never gets above about 140 Deg F. The ocean has a lot of mass and because it is liquid, temperatures tend to redistribute readily.

Well! in England we have the Gulf stream but who said it never exceeds 31c ? most of the great thinkers forget little things that can effect temperatures like LIGHTNING, ICE BURGS, SUN, WARM AND COLD STREAMS, WE could go on buts its February and I am still admiring a couple of large ferns and a couple of lavender plants that are flowering nicely

J.B.

It never gets much warmer than around 30 - 31 degree c.

Because the ocean has a very high heat capacity.

I personally believe it is through cumulonimbus clouds (thunderheads) probably forming earler in the day, through excess evaporation.