The area in northern France suffered rain and hail that damaged the grapes in mid-August just before the harvest, the industry's Champagne Committee said.
The pickers have had to be highly selective because the late rain caused a fungus known as botrytis bunch rot to affect the mature grapes, it said.
Some Champagne vineyards began harvesting their grapes on 26 August, among the earliest harvests since 1950.
A spring freeze had already wiped out 23 percent of buds in the region, the committee said.
But warm and sunny weather between May and July was extremely beneficial to the vines, giving them a "remarkable state of health" before the damage wrought by the storms and hail, it said.
The resulting grapes are of high quality with a "very promising" balance and good acidity.