The chief influences on Oregon’s climate are the relative distances from the ocean of given areas and the mountain ranges paralleling the coast.
The region from the coast to the Cascades has a temperate marine climate. Because of the moderating effect that nearby ocean water has on seasonal temperatures, summers are cool and winters are mild. The average temperature of the coldest month is well above freezing, and temperatures in the warmest month are generally below 21° C (70° F).
The Cascade Range and the Blue Mountains of northeastern Oregon have a highland type of climate, with cool summers and severe winters. The average January temperature is below freezing, and there is usually a snow cover for many months of the year. Snow is most abundant on the western slopes of the northern Cascade Range, where as much as 15 m (50 ft) accumulates during the winter. Precipitation in the coastal areas, the Cascades, and the Blue Mountains is the highest in the state. It reaches its maximum on the western slopes of the northern Oregon Coast Range, where it may exceed 3,800 mm (150 in) annually.
All of the western slopes of the Oregon Coast Range, Klamath Mountains, and Cascade Range capture moisture from the winds off the Pacific and have at least 1,300 mm (50 in) of precipitation yearly. The Willamette Valley and parts of the Blue Mountains have 750 to 1,300 mm (30 to 50 in) of precipitation.
The eastern two-thirds of Oregon, including the Basin and Range province and most of the Columbia Plateau region except the Blue Mountains, has a semiarid mid-latitude climate. Summers are warm and winters are cold. Precipitation is 250 to 500 mm (10 to 20 in) annually. There are within this large region a few deserts, or arid areas, with less than 250 mm (10 in) of precipitation yearly. One such area is found along the Columbia River, near Umatilla; another, in central Oregon just east of the Cascades; and a third, in the vicinity of Vale, near the state’s eastern border. "Oregon" © Emmanuel BUCHOT, Encarta, Wikipedia
Photos of European countries to visit
Photos of Asian countries to visit
Photos of America