One pretty constant comment I heard when I told people in the East that we were moving to Oregon was “Why do you want to move there? It rains all the time!!”
I thought, since the autumnal equinox is this Sunday, that it is a good time for a chat about Oregon’s weather. If you read this YOU, at least, won’t make blanket statements like what I heard ever again.
Not related in any way to marijuana, the North Pacific High is a high pressure system that begins to build in May and is usually at full stability by the beginning of July. This keeps moisture from the Pacific Ocean from moving inland, giving Oregon very dry summers. The eastern part of the state might get thunderstorms, as we experienced when we stopped to enjoy the hot spring , but typically, there is little precipitation in Oregon from June to October. The NPH begins to weaken in September, and by late October, moisture-laden winds are able to move on shore.
The Oregon Coast consists of a narrow strip of land between the Pacific Ocean and the Coastal Range. The coast is the most frost-protected part of the state, but it’s no Riviera. It’s the state’s coolest summer area with summer highs mostly in the upper 50s to low 60s. Although I had a sweater when we visited my sister on the coast in July, I needed to buy a sweatshirt! The coast experiences high winds and heavy rainfall during the winter and fog in the summer. 
The Coastal Range mountains rise up to about 4000 feet above the coastal strip. They effectively block the morning coastal fogs which sometimes last all day in summer. The area gets snow in the winter and the road signs indicate areas to pull off and put chains on your tires. The trees have a moss growing that reminds me of the type that grows in the Deep South. The western side of the Coastal Range is the temperate rain forest and this is the area where Oregon gets its reputation for “rain all the time.”
The Willamette Valley (by the way, Willamette rhymes with damn it-I had been saying it wrong all the years before moving here) is located between the Coast Range and the Cascades. This is the area where the Oregon Trail brought people and there is a good reason; it is a wonderful agricultural zone. Winters are cloudy and rainy with moderate freezes at night. Rains are often light and misty instead of downpours. You can tell a visitor from a resident because the visitors carry umbrellas; the residents just wear hats. Summers are pleasantly warm, sunny and dry. This is a major wine producing area with blind taste tests often winning over French wines grown at the same latitude.
When most people speak of “southern Oregon” they are speaking of the Rogue River Valley. Ashland, just north of the California state line, was where we spent a few days about 6 years ago and the concept to move to Oregon hit us. Summers are quite warm (temps over 95F are very common). Winters and springs are drier. The area is a major fruit production region.
The Cascades are volcanic mountains up to 10,000 feet and include Mt. Hood just east of Portland. Rising air currents wring the moisture out of the air coming off the Pacific which is why winters to the west, in the Willamette Valley, are rainy and cloudy. Again, roads are often snow-covered in the winter and chains are required on many. To the east, there is more sunshine and colder temperatures. Most of this area is under National Forest Service jurisdiction, which means there are many recreational areas.
North Central Oregon is located along the Columbia River. The River itself and Interstate 84 and rail lines parallel to it serve as a major transportation corridor. This is another rich agricultural area with some Oregon’s hottest summers. Winters are mild to the west of Portland increasingly colder to the East. It is another renown wine growing area.
Central and Eastern Oregon are isolated from western Oregon by the Cascades. With precipitation as low as ten inches a year, this area is high desert with cold and sunny winters. The area is sparsely-populated and towns are often very far apart. Mostly basin and range land, irrigation provides water for growing fruits and vegetables. 
So, you see Oregon has many climate zones and it doesn’t rain ALL the time.