<P> Oregon's climate is generally mild . West of the Cascade Mountains, winters are chilly with frequent rain, while light snowfall occurs a few days a year; temperatures can get very cold, but only occasionally, as the result of Arctic cold waves . The high desert region of the state is much drier, with less rain, more snow, colder winters, and hotter summers . An oceanic climate (also called "marine west coast climate") predominates in Western Oregon, and a much drier semi-arid climate prevails east of the Cascade Range in Eastern Oregon . Major factors determining Oregon's climate include the large semi-permanent high pressure and low pressure systems of the north Pacific Ocean, the continental air masses of North America, and the Cascade mountains . Oregon's population centers, which lie mostly in the western part of the state, are generally moist and mild, while the lightly populated high deserts of Central and Eastern Oregon are much drier . </P> <P> Precipitation in the state varies widely: some western coastal slopes approach 200 inches (5,100 mm) annually, while the driest places, such as the Alvord Desert (in the rain shadow of Steens Mountain) in eastern Oregon, get as little as 5 inches (130 mm). </P>

What is the weather like in oregon in the winter