How does weather shape France’s wines?

More and more wine is being grown in places with hot Mediterranean-style climates, Australia and California among them. But France's unique blend of landscape and weather – its terroir – has nurtured the grape for centuries. Experts have found that wine grows best in regions with cool winters that are a little above freezing and summers that average around 20–22°C/68–72°F. Plenty of sun is needed, of course (especially for reds), so vineyards are typically situated facing south, often with an eastward bent in places where west winds are a problem. River valleys close to oceans (Rhone, Napa, etc) allow mild marine air to filter in, but the vineyards need to be situated away from the top (to avoid wind) and the bottom (to avoid cold air pooling in the river basin). In general, heat increases the alcohol content, while mid-summer drought can raise the grapes' ratio of flavour-packed skin to juice. According to British environmental scientist Greg Spellman, global warming may not be a bad thing for wine. France's hot, dry summers of 1990 and 1995 produced memorable vintages, as did 2005 and 2006. However, the summer of 2003 overdid it: due to ultra-fast ripening, some grapes had to be harvested up to two months earlier than usual, and the result in many cases was a vintage that oenophiles found overly sweet and unbalanced.