The Hoh Ranger Station has a mean annual precipitation of 142 inches, with 174.6 inches recorded in 1961. Precipitation on Mount Olympus recorded in 1958 was 149 inches but this same year only 130 inches were received at the Hoh. Scientists who have been studying Blue Glacier on Mount Olympus since 1957 believe the heads of the western valleys receive 200 inches in some years.
Marine climates have greater precipitation in winter than in summer. Seventy-six percent of the yearly precipitation in northwest Washington occurs during the 6 months between October 1 and March 31. There is no definite time for the beginning and ending of the “dry” and “rainy” seasons, as the transition is gradual and variable.
The Olympic Peninsula would be well watered even if there were no mountains. The mountains, however, are responsible for wringing the bulk of the moisture from the saturated clouds and for creating local variations in the amount of precipitation. After passing over the mountains, the air is warmed in descending the leeward slopes. Consequently, the lowland areas on the lee side of the mountains are much drier than on the windward side. For instance, on the Olympic Peninsula at Sequim (pronounced Squim) the mean annual precipitation is less than 17 inches, and irrigation is required for successful agriculture.
Another prominent characteristic of the climate is the mildness of the winters at low elevations. In fact, western Washington is milder in winter than any other section of the continent in the same latitude. The reasons for this are the warming influence of the ocean and the protecting influence of the Cascade Mountains and of the Rocky Mountains against the flow of cold continental air westward to the coast.
Storm centers that pass eastward across Washington in winter shift to the north in summer, resulting in sunny summer weather that is delightfully cool under the influence of the ocean.
THE SOLEDUCK RIVER RUSHES THROUGH THE DEEP FOREST.
The Forests and Wildflowers
Our continent has a variety of climates, and each climatic area has its appropriate vegetation. Generally, the interiors of continents do not have forests, but have grass or desert vegetation. The most luxuriant forests develop near oceans where climate is sufficiently moist. This is true of other continents as well as North America.
The differences in the general character of our natural vegetation from coast to coast and border to border are apparent despite three centuries of man’s disturbance in the East and one century in the West. Sizeable samples of some of the many kinds of original vegetation are preserved in national parks and monuments. These are precious remnants of our plant heritage that become more valued year by year in proportion to their scarcity elsewhere.