Over the northern parts of the Pacific Ocean, the Maritime Polar air mass exists. This means that the air mass likely to be over the northern parts of the Pacific Ocean would be wet and cold.
An air mass blowing inland from the sea is usually wet and cold. This is because of the fact that it is saturated with water and cooled by rapid exchanges with the sea. Hence any time air is coming inland from the sea, we usually experiences cool moist breeze unlike air leaving the land and moving towards the sea which a is normally hot and dry.
