Prevailing Westerly Winds Oceans affect land areas near them, especially where winds blow over the water toward the land. These winds carry mild, maritime air. Parts of the west coast of the United States have marine west coast climates. So does much of Europe, where mountains do not block the maritime air mass.

The prevailing westerlies, blowing across the Pacific Ocean, carry moisture onto the west coast of the United States. These westerlies, like those blowing toward the western sides of Europe and southern South America, tend to come from the direction of the equator. There they were warmed more intensely by the sun, directly and indirectly, than if they had come straight from the west. Moving from the equator, they are deflected to the east by the Coriolis effect.