Sand warms up significantly faster than water when exposed to the same amount of solar radiation. This phenomenon is due to differences in "specific heat capacity." Water has a very high specific heat capacity, meaning it requires a large amount of energy to raise its temperature by even one degree. This is because water is transparent, allowing sunlight to penetrate deep into the surface and distribute heat over a large volume, and it also constantly circulates, mixing warm surface water with cooler deep water. In contrast, sand is an insulator with a much lower specific heat capacity. Sunlight only hits the very top layer of the sand, and because sand is solid, that heat is not easily transferred downward. As a result, the surface of the sand can become painfully hot on a summer afternoon while the ocean remains refreshing. This temperature difference is what creates "sea breezes"; as the hot air over the sand rises, cooler air from the water moves in to replace it. Conversely, sand also loses heat much faster at night, which is why beaches (and deserts) can feel surprisingly cold after the sun goes down, while the water retains its warmth for much longer.