Because a desert is mainly sand, it absorbs solar energy throughout the day causing the air above the sand to get extremely hot. However, in the evening, the heat energy is radiated back to the atmosphere and away from the surface quickly, resulting in a dramatic temperature drop. This is the reason a desert has the highest daily temperature fluctuations of any biome. The low amount of moisture in the air contributes to the rapid loss of heat by radiation at night. However, by the ocean, the water and sand absorb heat energy at different rates. It takes water a longer time to absorb heat but water retains that heat energy for a longer time, than does the sand. Therefore, during the daytime, the beach is hot when the sun is shining and at night, because the water retains the heat energy longer, the temperature doesn't drop as dramatically as it does in a desert. That is why coastal communities like Long Island have milder winters. The ocean helps to moderate the climate during the cold winter months.