Water has a high heat capacity. Explain how this property of water causes the oceans moderate the temperatures of adjacent land masses. If your not sure, check out differences in the average monthly temperature in Anacortes, Wa which is surrounded by water and Bismark, ND which is on the same latitude but with no surrounding water.
since water takes a long time to heat up and a long time to cool down, land masses along these coastal regions have more moderate temperature ranges than those of land masses inland on the same latitude