Oregon wine regions mostly lie in valleys between the southern Cascade Mountains that run through  the state and its Coastal Range to the west.  They are generally small and decentralized.  The northwest portion of Oregon is celebrated for its cool-climate grape varieties, including Pinot Gris, Riesling, Chardonnay, and especially Pinot noir.  The southern regions, along with the vineyards of the Columbia Gorge Valley are generally higher, much warmer and significantly drier than those  appellations in the northwestern quadrant of Oregon.  The rich variety of "micro climates" in southern Oregon (as well as in the Columbia Gorge AVA at Oregon's north central border) provide distinctive vineyard locations capable of nurturing high-quality Bordeaux and Rhone grape varieties, as well as French Burgundy varieties such as Pinot noir and Chardonnay.

Oregon's northern latitude brings long hours of summer sunshine to its vineyards, usually adequate to fully ripen grapes for Oregon wines. Occasional marine breezes breach the Coastal range, and help moderate the climate, causing the ripening process for wine grapes to be gradual. The combination of these conditions encourages complex fruit flavors, aromatics and nuances in these northern Oregon-grown wines, complexities that allow Oregon wineries to compete well with other world-class wineries.