Because Beidaihe is near the sea, the specific heat of water is large, that is to say, under the same heating or cooling conditions, the temperature of water changes little. Under the same sunshine conditions, the warming rate in coastal areas during the day is slower than that in inland areas, and the cooling rate in coastal areas at night is even smaller. Therefore, during the day, the temperature changes slightly in coastal areas and greatly in inland areas. In a year, the inland is hotter than the coastal area in summer and colder than the coastal area in winter. So Beidaihe is of course a summer resort.