Linfield University Wine Studies Reports

Document Type


Publication Date



This report describes the impacts of climate and phenology on vintage for the North Willamette Valley in Oregon in 2018. A relatively mild and dry winter set the stage for a 2018 growing season that was highlighted by a cool spring, a summer with low heat stress but high drought stress along with numerous regional fires, and a glorious October. The moderately cool spring led to a late start to the growing season with an average bud break of April 17th delayed by 5-10 days compared to average. However, a warm May through August brought plant growth timing to near average to slightly ahead of average in the region (average bloom June 12th, véraison August 15th, and harvest September 29th). The 2018 vintage ended with growing degree-day totals that were above average, but lower than the previous four vintages in the North Willamette Valley. The vintage saw a few mild frosts during early April, a warm and mostly dry bloom period, experienced a string of 60-90 days or more without precipitation during the middle of the summer, and had a prolonged harvest period from very beneficial weather conditions in October. Overall the growing season saw substantially lower heat stress (compared to the last few vintages) but greater drought stress compared to average.


This report was made possible by data provided by the participating vineyards.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.