I lived in Oregon for a summer and part of September and it was a glorious time to be there: very little ran fall and some nice temperatures that barely passed 80. Rainy season typically starts in November, though with global climate change,who knows what is typical now!
Portland has a great Oktoberfest and North by Northwest in September. about 8 years ago
We visited in Medford OR last year in late September through October and loved it! The fall foliage was out, days were sunny and warm, evenings just a little bit cooler-perfect in every way! Make sure to visit Ashland, right nearby-cute town for strolling, a lovely park, ice cream shops-lovely! about 8 years ago
Lived in Salem for 11 years. The early fall is idea. Be sure and check out the Bend (central Oregon). Oh, also go to Crater Lake, it's amazing. There is a lodge right on the rim. If you can't stay the night go there and walk around, have a lunch. Go to Cannon Beach on the coast then drive south along the coast. Joseph on the eastern side of Oregon is great too. Another nice lake and place to stay. almost 8 years ago