Leading California wine regions at risk

Global warming and increasing wildfire risk threaten viability of elite wine-growing regions in California - but others may boom, a new report says. 

Mendocino and Monterey could become increasingly favourable for premium vintages under shifting climate patterns, while Napa and Sonoma may face increased pressure in grape cultivation. 

The US is the fourth-largest wine-producing country by output volume, and approximately 80% of its production occurs in California. 

Since the 19th century, California’s premier wine-growing regions have been the Napa Valley and Sonoma County, thanks to their favourable microclimates. 

But grape yield and quality are very sensitive to the local environment, which means that the climate crisis could shake up California’s wine industry. 

The new study shows that established regions including Napa and Sonoma could struggle to sustain their wine production under severe climate change. Others, like northern and coastal California, could become new wine-growing powerhouses.

“Our findings reveal that the outlook for Mendocino and Monterey is uniquely promising because of a dual trend: they are projected to experience both increasing climatic suitability for wine-growing and a decrease in extreme fire-weather days,” said Dr Yusuke Hiraga, an assistant professor at Tohoku University in Sendai, Japan, and author of the study in Frontiers in Climate. 

“This combination makes these areas stand out as comparatively favourable expansion zones, distinct from many other regions with either rising suitability alongside increased wildfire weather or declining suitability

Together with Takuya Matsumoto, a masters student at Tohoku University, Hiraga modeled California’s current and future climatic suitability for wine grape cultivation. 

They focused on 379 wine-growing locations listed in the California Wine Institute, predominantly in the North Coast region and across the Central Coast.

To forecast climate change, the authors mapped projections from global climate models onto a 4km-by-4km grid across the mainland US. 

They also considered alternative carbon emission scenarios. 

The authors likewise modelled the shifting weather conditions linked to wildfire risk and expected severity within each cell. 

The results showed that the suitability of currently important wine-growing regions, like Napa, Sonoma, San Luis Obispo, and Santa Barbara, is likely to decline strongly under severe climate change. 

In contrast, suitability was predicted to increase greatly in Mendocino, Monterey, and in central to southern coastal areas. 

“While our study highlights long-term shifts in climatic and fire-weather suitability through the end of the century, it does not attempt to predict a specific timeline for when emerging areas will surpass currently established regions in wine-growing potential,” Hiraga said. 

“Such a precise forecast is complex, as the future of viticulture is shaped not only by climate change and wildfire weather but also by a wide array of anthropogenic factors.”

For more info, here is the original research  article: https://www.frontiersin.org/journals/climate/articles/10.3389/fclim.2026.1838268/full