LIGNORELLES, France — On a brisk late September morning in the heart of Chablis wine country, grape pickers haul large and heavy buckets over their shoulders, drenched in sweat as they climb the steep slope of the Vau de Vey vineyard.

It’s the final day of the harvest at the Domaine Roland Lavantureux winery, and workers are handpicking the last of the prized Chardonnay grapes that will eventually be transformed into the bright and high-end Premier Cru that is bottled by the estate.

But wine lovers may struggle to get their hands on the 2024 “millesime” — wine that comes from a single year’s harvest. It will be sold in smaller quantities than usual.

Much of France’s wine country faced one of the wettest years on record in 2024 so far amid a changing climate, after years of challenges to vineyards and wine quality caused by drought and heat. At the Lavantureux estate, the picking lasted just nine days — about half the usual time — after a year of unpredictably harsh weather marked by frost, hail, record rainfall and the spread of a dangerous fungus that has left Chablis growers on edge.

“I have been working here since 2010. This is my most difficult year,” says winemaker David Lavantureux, who follows in the footsteps of his father, Roland. “And all the old-timers will tell you the same thing. It’s been a very difficult year because the weather has been so unpredictable. We have not been spared a single thing.”

The ordeal began in April with the frost. Then in May, a double hailstorm pummeled the region. Then came relentless rain, right up to the harvest. According to the Burgundy wine federation, nearly 2,500 acres of vines in the Chablis country were affected by the May storm. And the excess moisture allowed a destructive mildew fungus to thrive.

Once entrenched, the disease causes huge crop losses and can also affect wine quality. Together with his brother Arnaud, David fought hard to try and control mildew with various treatments, which were washed away by the rain and didn’t prove effective.

“On our estate, we’re looking at losses of 60 to 65%,” David Lavantureux said. “It’s going to be a low-yield year.”

Located in the northern part of the Bourgogne region, the vineyards of Chablis have traditionally benefited from a favorable climate — cold winters, hot summers and annual rainfall of 25 to 27 inches.

But climate change is altering those conditions, bringing unseasonably mild weather, more abundant rainfall and recurrent spring frosts that were less common in the past.

The frost damage is particularly frustrating. A similar phenomenon hit French vineyards in recent years, leading to big financial losses. Scientists believe the damaging 2021 frost was made more likely by climate change.

To adapt, winemakers have adopted creative solutions. Cutting the vines later helps delay bud burst and reduces the vulnerability to late frost. Anti-hail devices have also been deployed in a bid to lessen the damage.