Hi Marshall and thanks for your great question! The temperature of the sea surface and the air directly above it can be different because of differences in the amount of energy it takes to heat water compared to air. Water has a higher heat capacity than air, which means that it takes more energy to heat water by 1 degree Celsius than it does to heat air by 1 degree Celsius. The consequence is that water changes temperature much more slowly than air – it takes longer to heat up in summer and longer to cool down in winter, for example. Because the air and water change temperature at different rates, they can be quite different in a single location in the ocean that is exposed to the same amount of energy from the sun. The temperatures in a given location are also influenced by local weather – the movement of air by winds, and the movement of water by ocean currents – which may transport air or water with very different temperatures across long distances.
Question submitted by Marshall, Cool CA, USA