Harsh weather in the main wine-producing countries in Europe means global production is expected to drop by 8% this year.
Output in Italy is expected to be down by 23%, in France by 19%, and in Spain by 15%, according to the International Organisation of Vine and Wine (OIV).
Spring frosts and summer heatwaves are to blame, according to the European Commission, which estimates the European Union’s wine grape harvest will fall to a 36-year low in 2017.
Globally, output could plunge to its lowest level in more than 50 years.
Based in Paris, the OIV said global production was likely to fall by 246.7m hectolitres this year.
A hectolitre is 100 litres – just over 133 75cl bottles.
Most of the main wine producing regions in France, including Bordeaux and Champagne, have been affected by the poor conditions, with the government projecting the lowest output for decades.
Wine lovers need not necessarily be alarmed, however, because prices and supply depend not only on production, but also on stocks from previous years.
The quality of wine from landmark regions has an impact too, and French producers say there is a good chance that standards will be high.
In other parts of the world, meanwhile, supplies are holding up well.
In the United States output is expected to be down just 1%, at 23.3m hectolitres.
A rise of 6% is expected in Australia, while in Argentina, a jump of 25% could be on the cards.