Winemakers have also had to contend with spring frosts and hailstorms this year and the country's agri-food agency Coldiretti is anticipating a 10-15 percent fall in volumes.
But producers say a good year for drinkers is still on the cards at the start of a harvest that will not be completed until around the end of October.
Traditionally, the start of the Italian harvest is celebrated in the north of the country, where the first chardonnay grapes were picked on Friday at the Faccoli family winery in the Franciacorta region near Milan.
But the acclaimed sparkling wine area was beaten to the punch this year with picking already underway in Sicily and at least one producer in neighbouring Piedmont having started bringing in his early-ripening grapes on July 29th.
Across the country, harvest start dates were expected to be, on average, around ten days earlier than usual.
But the pattern is uneven and the impact of the current broiling conditions on Italy's top wines remains to be seen.
"There are some thirsty vines out there in the valley," said Manfred Ing, the South African winemaker at the Querciabella estate in the Chianti Classico region of Tuscany.
"With the heat arriving so early this year, the vines have very small bunches and berries so from a qualitative point of view we are in for some good grapes once it finally rains, which it always does.
"Yields will probably be down but this is not a problem for us from a fine wine making point of view.
"Being dry and hot there is also zero disease pressure in the vineyards.
"The intensity of the heat and lack of water means the vines have almost gone into survival mode with a delayed maturation occurring."
Ing told AFP his vines were only just starting to go through veraison (colour change), pointing to a September start for picking of the estate's white grapes.
"Fingers crossed we get some good rain and make some rock star wines again this year!"
Italy's wine sector, which had sales of €10.5 billion in 2016 and employs some 1.3 million people, is currently one of the most dynamic sectors of an otherwise struggling economy.
Coldiretti said figures for the first four months of 2017 pointed to the value of exports growing at nearly five percent this year, from €5.6 billion in 2016.
The agency also predicted that Italy would retain its status as the world's biggest producer of wine by volume with rivals France and Spain having also been hit by frost, hail and rainstorms this year.
Although Italy is the biggest producer by volume, France's production is significantly more valuable with the exports of the likes of Bordeaux, Burgundy and Champagne worth €8.2 billion last year.