But desert cities have extreme temperatures and will get cold in the winter … . Some of the most temperate cities in Oregon are on the Southern Coast (Brookings, Gold Beach). But the best year-round weather is said to be in the Rogue River Valley (Roseburg) and in Southern Oregon (Ashland, Medford).hat city in Washington state has the warmest weather all year round? The cities of Kennewick, Pasco and Richland (Also known as the Tri-Cities) get 300 days of sunshine a year.