This erosion process continues today, but on a much smaller scale. As glaciers advance and retreat, rock is plucked, transported, and deposited by moving ice. The finely ground rock created by the glaciers often makes the glaciated rivers look milky when the glaciers are melting. Olympic National Park Climate Olympic National Park climate is predominantly a marine type with cool summers, mild but rather cloudy winters, moist air, and a small daily range in temperatures. The weather is extremely unpredictable.
Rainfall is quite varied.
Sequim, on the northeast side of the peninsula receives an average of about seventeen inches of precipitation a year. While forty airline miles to the west, in the rain forest valleys, precipitation can average 140 to 167 inches per year. There is no definite time for the beginning and ending of the dry or rainy seasons. The transition is gradual and variable. In lower elevations and near the water, snow rarely exceeds a depth of six to ten inches or remains on the ground more than a few days.