This report describes the impacts of climate and phenology on vintage for the North Willamette Valley in Oregon in 2020. A mild and dry winter in 2019-20 was followed by a dry growing season continuing the ongoing drought concerns for Oregon and the majority of the western US. The spring was relatively cool with mild frosts in early April, then followed by wide swings between early season heat then cool, wet conditions leading up to and during flowering. The result was widespread issues with fruit set leading to generally high amounts of shatter, smaller berries and clusters for many in the region. A relatively heat stress free summer was leading into what looked like a decent September weatherwise until the Labor Day extreme wind event, which was followed by catastrophic fires and smoke for days. Growing degree-day totals for 2020 ended up similar to the 2004, 2006, 2013, and 2018 vintages. Across twelve sites in the region the phenological timing averaged April 11th for bud break, June 11th for bloom, August 17th for véraison, and September 27th for harvest. Growers reported generally low disease pressure, relatively low pest pressure, little to no bird pressure until later in the picking window, and a harvest that presented very good quality fruit at moderate to substantially lower yields.
Jones, Gregory V., "Vintage Report 2020: North Willamette Valley" (2021). Linfield University Wine Studies Reports. Report. Submission 43.