Wine output in France, the world's second largest producer, may fall by as much as 13% this year after vineyards were hit by adverse weather including hail, frost and a record-breaking heatwave, the farm ministry said on Friday.
In its first estimate for 2019, the ministry forecast production in a range of 42.8 million hectolitres to 46.4 million hectolitres, down 6% - 13% from 49.4 million hectolitres in 2018.
A hectolitre represents 100 litres, or the equivalent of about 133 standard wine bottles.
The ministry's initial 2019 forecast range was also 2-5% below the average production of the past five years.
"In many vineyards, flowering occurred in unfavourable weather conditions (rain and cold)," the ministry said in a note. "Heat and hail have also contributed to a decline in production potential."
Western growing regions including Bordeaux were particularly affected by poor flowering conditions during spring, while some southern areas saw grapes scorched during a heatwave in late June, it said.
France recorded its highest-ever temperature at 45.9 degrees Celsius (114.6°Fahrenheit) at the end of June during an intense hot spell that fuelled wildfires and withered some vineyards.
Lack of rain in the past month has also worsened drought conditions in parts of the country, and the farm ministry said soil moisture levels in most wine regions were below normal.
Like hail, frost also caused localised damage this year, including in the Bordeaux and Burgundy regions, it said.
The Champagne area saw good flowering conditions and limited weather damage, although production was expected to be below last year's, the ministry added.
French wine grapes are harvested in late summer and early autumn, and the ministry said its estimates were tentative given uncertainty over conditions until the harvest.