Widespread rain across Australia's main grape-growing regions on the 20-21 February has severely affected prospects for a previously promising vintage.

Harvesting has only just started but predictions were for the first year-on decrease in yields in seven years. Although completion is still some six to seven weeks away, expectations are for a total output of around 1.37 million tonnes – a decrease of 14% on 2002.

The low yields can be attributed to the widespread drought across Australia throughout winter and spring. Despite some rain in January, the intense heat has limited berry size and restricted the development of bunches.

In January Angus Kennedy, operations and technical director of BRL Hardy, compared the conditions to 1995, when yields were between 10% and 25% below expectations.

The recent rain has led to many producers seeing their drought-stressed small berries filling out and splitting. The premium inland districts such as the Mclaren Vale and the Barossa Valley, where the effects of the drought were most extreme, look to have been worst hit by this.

The likelihood of fungal infections such as mildew and botrytis has also been increased by the hot and damp conditions.

The drought has been less severe in coastal regions such as the Yarra Valley and Geelong and the recent rain may even have the beneficial effect of freshening up the grapes. The full impact is not likely to be known until the harvest is completed in April.

Written by Richard Woodham, and David Pearce3 March 2003