In Eugene, expect rain—a lot of it. There is no avoiding this part of the climate, and you can most definitely expect it for six or more months of the year. However, this near-constant downpour adds to the lush beauty of the UO's campus, making everything very green. Although it rains a lot, don't expect a five-hour storm every day. The rain is light and manageable. Once you get used to lugging around your raincoat at all times, you won't mind it. Students often complain about the rain, but most learn to adjust and dress appropriately. Many appreciate the sun much more when it comes around, and there is really no better place than Eugene on a warm spring day. It's key to carry an umbrella or a raincoat all the time because Oregon's climate can catch you off guard pretty easily.
Oregon generally receives a mild dose of all four seasons, without any especially excessive weather. This is nice because you won't get a scathing hot summer or a blizzard in the winter. The autumn is cool and calm, winter cold and wet, and spring warm and bright. If you're around for summer, expect high temperatures and a lot of opportunities for fun in the sun.