Answer:
High specific heat capacity
Explanation:
For the same temperature change, a body of water (with a high specific heat capacity) can absorb a larger amount of heat than the land (with a small specific heat capacity)
Thus, the seasonal temperature of the sea varies over a relatively narrow range.
However, the temperature of the land shows wider seasonal variations.
In summer, the cooler water keeps land areas relatively cool. In winter, the water is warmer than the land, so it keeps land areas relatively warn.
Thus, coastal climates are usually more moderate than inland climates.
For example, Winnipeg and St. John's are two Canadian cities close to the 49th parallel.
Winnipeg, in central Canada, has average temperatures of -18 °C in January and 27 °C in July, a range of 45 °C.
The corresponding temperatures for St. John's, 3000 km to the east on the Atlantic coast, are -8 °C and 21 °C, a range of 29 °C