Wine production is deeply intertwined with climate, and as global temperatures shift, understanding how grapevines respond to environmental stressors is more critical than ever.
Dr. Jason P. Londo, an associate professor of horticulture at the School of Integrative Plant Science at Cornell University, presented research at the 2025 Ohio Grape & Wine Conference that explores grapevine hardiness, adaptation to climate change and the implications of shifting weather patterns on viticulture.
His work provides valuable insights for vineyard owners looking to optimize grape cultivation in diverse climates as well as resources to aid in vineyard management.
Grapevines have different abilities to survive freezing temperatures, a trait known as cold hardiness, which Londo discussed. Most wine grapes come from Vitis vinifera, a species domesticated in Europe that thrives in mild climates. However, North America has over 20 wild grape species that can survive much colder temperatures, some as low as -40º F. Scientists breed these hardy traits into cultivated grapes to improve their resistance to cold.
Londo’s research highlights that while many grapevines can withstand harsh winters, their response to extreme cold depends on genetic factors and environmental conditions. His team examined how vines acclimate to cold, the mechanisms that protect them and the role of fluctuating winter temperatures in triggering dormancy and deacclimation, or the loss of the ability to tolerate freezing temperatures.
As Londo explained, grapevines undergo three key phases to survive winter: In autumn, as temperatures drop vines build resistance to cold, known as acclimation. During mid-winter, vines reach peak cold tolerance, or maximum hardiness. Lastly, as temperatures warm in spring, the vines lose their cold resistance in the process called deacclimation.
Londo’s research revealed that different grape varieties transition through these phases at varying speeds. For example, Cabernet Sauvignon acclimates and deacclimates slowly, making it more vulnerable to sudden spring freezes. In contrast, Maréchal Foch deacclimates rapidly, increasing its risk of early-season frost damage.
As the climate continues to change, it will impact both vines and grapes in vineyards. Photo courtesy of Howard F. Schwartz, Colorado State University, Bugwood.org
Over the past decades, winter temperatures have been steadily increasing across key wine-producing regions. Londo presented temperature data from various locations, including Ohio and New York, showing that winter lows have warmed by 5º to 15º since 1960. However, while warming may seem beneficial by reducing the risk of deep freezes, it also introduces new challenges: Unstable winter conditions and warmer winters disrupt traditional cold-hardiness cycles, increasing susceptibility to late-season frost damage.
Additionally, polar vortex storms and sudden temperature swings caused by climate change weaken the jet stream, allowing arctic air to dip southward. These abrupt drops in temperature after periods of mild weather can severely damage grapevines.
Lastly, as winters continue to warm, vines accumulate chill hours sooner, leading to earlier bud break. If a sudden freeze follows, significant crop loss can occur.
To aid vineyard management, Londo’s team has developed predictive models assessing temperature fluctuations and cold hardiness in order to mitigate cold damage to vines. These models integrate real-time weather data and grapevine response patterns to help growers anticipate risk. Using tools like the Cornell Cold Hardiness System, vineyard owners can monitor bud cold-hardiness levels, identify potential freeze events and make informed decisions about frost mitigation strategies.
Understanding how grapevines respond to climate variability is essential for sustainable wine production. While warming trends allow for the cultivation of new grape varieties in traditionally colder regions, they also introduce risks like premature bud break and increased frost vulnerability.
Londo’s research shows that by leveraging genetic insights, predictive models and innovative vineyard management strategies, growers can mitigate these risks and adapt to the evolving climate landscape. As research continues, the wine industry must remain proactive in embracing scientific advancements to ensure high-quality grape production in an increasingly unpredictable environment.
For more information on the Cornell Cold Hardiness System and access to the Cornell Grapevine Freezing Tolerance monitoring program and prediction application, visit cornell-tree-fruit-physiology.shinyapps.io/North_America_Grape_Freezing_Tolerance.
by Ken Griffin
