One of the most problematic issues regarding wine quality revolves around the question of rain. But the rain that hit heavily on Napa and Sonoma vineyards for several days in early April caused no damage.

Indeed, it was a blessing. However, rain during the harvest season in the fall is another story. In most areas of the northern hemisphere, where grapes are grown for wine, even light rains can pose enormous problems.

Timing is everything. Grapevines are hardy and can last without irrigation for many decades. Vines send their roots deep into the soil to find water. Some grapevines have survived for more than 100 years without intervention from humans.

The problem with the weather, however, is not about the vines themselves, but about the fruit they produce. And every sort of weather deviation from the normal can have terrible consequences. Here are just a few:

Rain: Even if rain is particularly heavy and floods the vineyards, as has happened numerous times around the world, if the rain occurs while the vines are dormant, turning a vineyard into a lake is not a major problem. Warmer weather eventually solves this.

Flooding can, of course, cause some vines to become uprooted, necessitating replanting. But that situation is rare.

Frost: Most French cultivars, the family of grapes that produce the finest wines (Vitis vinifera), can be damaged by too much very cold weather. This is what occurred in late March and early April this year in the Champagne district north of Paris.

It was estimated that nearly half of all grapevines in the district were damaged by frost. With champagne prices already averaging more than $50 per bottle in the United States, importers now suggest that prices will go even higher.

Heat: In the middle of summer in the northern hemisphere, temperatures rising above 100 degrees Fahrenheit do not pose a problem for grapevines if the duration of the heat is short. But if the heat wave lasts for several days, growers can have a difficult time keeping the vines growing.

Irrigation helps, but at a time when global climate change seems to be inevitable, growers are now giving serious consideration to increasing the number of leaves vines produce to create additional shading of fruit.

Humidity: If a vineyard encounters significant humidity, one risk is that vines might develop maladies like rot or mildew, requiring spraying to protect the fruit. Not only is spraying expensive, but it is not always a perfect solution.

Wind: Regular and persistent wind can actually assist the development of certain flavors and some varieties. Wind can be beneficial with Pinot Noir and Syrah. But when the wind is excessive and/or long-lasting, grapevines may stop photosynthetic reactions, which reduces flavor maturation.

The result can be wines that have deficient flavors. In some areas of the world, this is difficult to cope with, but California typically does not have this problem.

The above five climate impacts are not the only problems grape growers will encounter in the course of a year and in some areas, two or more of these issues will arise. And almost all solutions entail costs that growers must absorb.

Grape growing and wine making may sound like a charming, idyllic way to make a living, but as one grape grower told me decades ago, "Don't forget: that bottle of wine you'll enjoy this evening is the result of farming. And farming is no picnic."

To find out more about Sonoma County resident Dan Berger and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate webpage at www.creators.com.

Photo credit: Karsten Würth at Unsplash