A welcome sign of spring each year for grape producers is budbreak, the moment when tiny buds on the vine start to swell and green leaves appear. Budbreak varies by region, variety and even vineyard topography, but in Sonoma County, unseasonably warm weather caused buds to burst early, reported Bill Swindell in the Press-Democrat.

“Perhaps it's the new normal,” said Jen Walsh, the winemaker at La Crema Winery in the Russian River Valley, commenting about long-term change due to global warming.

The Carneros region that borders San Pablo Bay is typically the first wine appellation to experience bud...