Making Sense of Coldwater Ocean Currents
The currents run counterclockwise. That's why the Humboldt Current cools the Pacific coast of South America, because the water is coming from the "six o'clock" position in the Antarctica. But in the Northern Hemisphere, the "six o'clock" position is warm water near the equator, which warms Oregon and Washington.

In the northern hemisphere, the cold Labrador current cools land to its west. That's because the water is coming from the "12 o'clock position near the Arctic. On the other hand, the west coast benefits from warm water currents running in a counterclockwise direction. That's because the "6 'oclock" position in the northern hemisphere is near the tropics, which brings warm water to Washington and Oregon at the "2-3 o'clock" position.

All other things being equal, colder air carries less moisture than warm air, and land near cold water currents is dryer than land near warm water currents.