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.
Jones, Gregory V., "Vintage Report 2018: North Willamette Valley" (2019). Linfield College Wine Studies Reports. Report. Submission 2.