@hasmis not "cannot." Sea surface temps can, and have exceeded 30c. Simply put, it's a matter of how hot the troposphere gets:
https://skepticalscience.com/tropical-terhmostat-limits-sea-surface-temperature-to-30C.htm
@hasmis
The link explains better than I can. The sensors have only been in the ocean for the past 30-some-odd years, not all of planetary history. Yes, for this brief window of human monitoring, the temperature has not exceeded 30C, bit there is no scientific or physical law that requires that; it's the result of a complex set of other factors, all of which are changing.
@trianglman 30c is too precise. Have the floats shown 35? Is there a cliff in the distribution? A small section of a confined sea could go over, but if there is open convection in the Pacific, then there is a soft limit, of around 30, but there is no physical law, like 100c.