Everyone who has walked barefoot on a beach in the summer has noticed how fast the dry sand gets hot in the morning. This should keep the sand from getting as hot as if it were black. High thermal conductivity means that heat transfers through the material. With a low specific heat, the sand is easy to heat up. It is also easy for it to cool off.
Water has a high specific heat.
It is hard to heat up. Notice that the water in the pool stays cool. Even though it absorbs relatively little heat from the sun, it only takes a little to heat it up.