The overall volume of wine produced was 84 million litres, well below the average of 105 million, the federal agriculture office said on Thursday.
On the positive side the grapes were of very good quality this bodes well for the vintages to be bottled.
The year was marked by erratic weather and regional differences across Switzerland’s wine growing areas.
A cold and wet spring delayed the flowering of the vines, the agriculture office.
A mild summer and plenty of sun in the autumn compensated for this but in most regions the grape harvest occurred at least two weeks later than normal and in some regions continued until mid-November, the office said.
Because of the weather, grapes were in some cases significantly smaller than average.
In the southern canton of Ticino, viticulturists enjoyed a large harvest, in contrast to other regions.
Wine growers in Geneva and the Three Lakes region linking the lakes of Neuchâtel, Biel and Murten were hit hard by a hailstorm on June 2oth which laid waste to some vineyards.
The canton of Neuchâtel was most severely impacted by the hail, contributing to a 54 percent drop in wine production for the canton in 2013.
Swiss vineyards covered a total of 14,883 hectares, 37 hectares less than in 2012.
Switzerland’’s wine is largely produced from grapes grown in the west and south of the country in the cantons of Geneva, Neuchâtel, Ticino, Valais and Vaud.
Almost all of the wine is drunk within the country with less than two percent exported, largely to Germany.