Climate and wine style

If you know only one thing about a wine's origin, growing-season temperature tells you the most about how it will taste.

Cool climates: higher acidity, lower alcohol, lighter body, more herbal and floral character, later-ripening varieties struggle. Chablis, Mosel, Champagne, England.

Warm climates: riper fruit, higher alcohol, softer acidity, fuller body, more polished tannin. Barossa, Napa, Mendoza, Puglia.

Maritime climates have a smaller annual temperature range and more rain; continental climates have hot summers, cold winters and greater vintage variation; Mediterranean climates have warm dry summers and mild wet winters.

This is why the same grape produces such different wine in different places — the reason Chablis and Californian Chardonnay share a variety and almost nothing else.

Diurnal range — the gap between daytime and night-time temperature — matters almost as much as the average and is discussed far less. Grapes accumulate sugar in the heat of the day and respire acid away at night if the night stays warm. Somewhere with hot days and cold nights, like Mendoza or eastern Washington, can ripen fruit fully while keeping acidity that a place with the same average and warm nights would lose.

Climate change has made all of this a moving description rather than a fixed one. Regions that were marginal fifty years ago now ripen reliably, and several classically warm regions have moved past the point where more heat helps. Harvest dates across Europe have moved earlier by two to three weeks over four decades, and varieties are being reconsidered in places that had not changed them in centuries.

The practical consequence for a drinker: climate tells you what to expect before you know anything about the producer. A cool-climate Syrah and a warm-climate Syrah differ from each other more than a cool-climate Syrah differs from a cool-climate Pinot Noir, and knowing which you are holding is more useful than knowing the vintage.