Cool Climate Viticulture: Character and Grape Suitability

Gregory V. Jones, described by GuildSomm as a professor and research climatologist at Southern Oregon University, writes that climate is "arguably the most critical environmental aspect in viticulture and wine production." Using average growing season temperatures (April through October in the Northern Hemisphere), he shows that quality wine production is limited to 13 to 21°C (55 to 70°F) worldwide, and that averages below 13°C are typically limited to hybrids or very early ripening cultivars. A University of East Anglia study reported by Wine Spectator in 2016 treats 13°C (55°F) as the minimum needed for successful cool-climate viticulture. In Jones's comparison, varieties best suited to a cool climate "tend to produce wines that are more subtle, with lower alcohol, crisp acidity, a lighter body, and typically bright fruit flavors." He adds that geology or soil does not produce these general differences; their impact is found in subtler differences within the same climate or region.

• Jones notes that average growing season temperatures are functionally identical to growing degree-days, but are generally easier to calculate
• The Winkler Index, as updated by Jones et al. (2010), divides Region I into Ia (850 to 1,111 degree-days, Celsius units) and Ib (1,111 to 1,389), where only very early ripening varieties achieve high quality, mostly hybrid varieties and some V. vinifera; Region II (1,389 to 1,667) is where early and mid-season table wine varieties will produce good quality wines
• Jones warns that a cultivar grown in too cool a region, or in too cool a vintage, gives lower sugar levels, unripe flavors and unbalanced wines
• WSET describes Champagne as a region with a cool climate and variable weather, where growers cannot always rely on grapes to ripen fully each year; blending wines from a few vintages helps to even things out

Jones finds that the growing season temperature limits for grapevines occur mostly in the mid-latitude regions of the continents, but cautions that latitude is often misused as a guide to climate suitability: Bordeaux and the Napa Valley are both known for Cabernet Sauvignon, yet Bordeaux is substantially more humid, with much greater rainfall during the growing season. WSET notes that UK wine regions typically sit between 51 and 53°N, beyond the 30 to 50° latitude band typically considered suitable for high-quality wine, and that long daylight hours there allow slow ripening, giving time for complex aromas and flavours to develop. Warmer climates often produce wines with lower acidity, but WSET adds that high altitude and cool night temperatures can preserve their freshness.

• Jones lists the relative amount of insolation, the composition and color of the soil, the local topography and slope aspect, and drainage as major factors in a vineyard's temperature structure, especially at night
• On nights when radiation inversions form, a warmer thermal belt develops upslope, generally 30 to 300 meters off the valley floor, giving some protection from the coolest valley-bottom sites (Jones)
• Wines of Germany says the Mosel's protected valley location makes it one of the warmest climates in Germany, with steep slate slopes that store the sun's heat during the day and release it at night
• New Zealand Winegrowers attributes Marlborough's wines to a cool yet high sunshine climate, low rainfall and free-draining, moderately fertile soil; its Awatere Valley sub-region is cooler, drier, windier and often with a degree of elevation

Jones's first principle is to match the cultivar to the climate so that it grows in its optimum zone, where it more consistently produces higher quality wine and tends to balance four ripeness clocks: sugar accumulation, acid respiration, phenolic ripeness and fruit character. Pinot Noir, in his account, spans cool to lower intermediate climates of roughly 14.0 to 16.0°C (57 to 61°F), and outside those bounds is typically unripe or overripe. Chardonnay grown in relatively cool climates (about 14 to 16°C) gives an elegant, crisp style flavored more by apple, pear and fig. Cabernet Sauvignon is an intermediate to warm to hot climate cultivar at roughly 16 to 20°C, with Hawke's Bay, New Zealand near its lower climate limit.

• Riesling: WSET notes that many of Germany's wine regions have a cool climate with an annual threat of spring frosts; Riesling buds late, which minimises that threat, and retains its high acidity long into the growing season
• Sauvignon Blanc: WSET says it thrives in cool to moderate climates; if the climate is too warm, the grapes ripen too quickly and the variety's distinctive herbaceous aromas will not develop
• Marlborough: New Zealand Winegrowers records that until the 1970s the conventional wisdom was that the South Island was too cold to grow grapes; some of the original vines, unsuitable for the cool nights and dry summers, were replaced with Sauvignon Blanc and Pinot Noir in 1975
• England and Wales: WSET reports that Pinot Noir, Chardonnay and Meunier dominate plantings, with hardy German varieties and hybrids such as Bacchus, Seyval Blanc, Ortega and Solaris also grown

WSET calls climate the single biggest influence on a wine's acidity: wines from cooler regions tend to hold onto more of their tartaric and malic acid, because the vine metabolises malic acid as temperatures rise during the ripening period. Jones writes that most cooler climate cultivars achieve greater typicity in ripening periods with higher diurnal temperature ranges, where daytime temperatures are high enough to ripen fruit while nighttime temperatures slow respiration and metabolism. He cites some evidence that average nighttime temperatures below 12°C (54°F) in the last month of the vintage are best for cultivars that need cooler nights. The ripening period, from véraison to harvest, averages 40 to 60 days for most cultivars and regions, with research pointing to the last 30 days as the time when most polyphenols, color, flavor and aroma compounds develop.

• Methoxypyrazines give Sauvignon Blanc, Cabernet Franc and Cabernet Sauvignon their green bell pepper, tomato leaf and cut-grass notes; WSET says levels are higher in less ripe grapes and tend to decrease as ripening progresses
• WSET reports that Sauvignon Blanc grapes grown in the shade have nearly double the amount of this green bell pepper compound compared with those grown in sunlight
• Rotundone gives Syrah its peppery aroma; Jones says high concentrations typically result from a cooler climate with higher diurnal temperature ranges
• In a cool Washington season, WSU Viticulture and Enology reported ripe flavors developing at lower sugar (°Brix) and higher acidity than usual, noting that a titratable acidity of 9 to 11 g/L and pH of 3.0 to 3.2 in white grape must is not unusual for cool climate conditions

Wines of Germany says nowhere in the world has more steep vineyards than the Mosel, which with its tributaries the Saar and Ruwer is considered Germany's oldest wine region: around 5,000 winegrowers cultivate 8,287 hectares (2025), half of it on steep and terraced sites with a slope of over 30 degrees, and Riesling covers 5,156 hectares. In New Zealand, Marlborough holds almost 31,000 hectares of vines, around two thirds of the national total, according to New Zealand Winegrowers, and Central Otago is the country's southernmost wine region. WSET reported in 2022 that English and Welsh vineyards cover 3,800 hectares and that, despite rising temperatures, even the warmest regions have a very cool climate.

• Mosel: Wines of Germany gives the Bremmer Calmont a gradient of up to 60% and calls it the steepest sloped vineyard in Europe; it takes up to 1,800 hours of manual work per hectare, and only 13 of its 22 hectares are still planted
• Marlborough: three-quarters of New Zealand's Sauvignon Blanc is planted there (22,000+ hectares), and the variety makes up 72% of the country's wine production and 86% of its exports, per New Zealand Winegrowers (accessed 2026)
• Central Otago: New Zealand Winegrowers describes Gibbston as the highest subregion, where a cooler climate and north-facing hillside vines ripen later than neighbouring subregions, and Wanaka as cooler and slightly wetter than the rest of the region
• United Kingdom: Wine Spectator reported in 2016 that UK vineyard land grew by 148 percent from 2004 to 2013, to just over 4,650 acres

Jones's table of climate and wine style gives cool-climate wines a lean, tart fruit style, apple and pear flavors in whites, cranberry and cherry in reds, a light body, crisp and tangy acidity, low to moderate alcohol and a subtle, elegant overall style. Within a region, he notes, vintage climate variability can bring quite large differences in wine style and quality from year to year. WSET adds that acids act as natural preservatives, allowing fine wines to age for a decade or more. Weather is the grower's constant risk: in cooler, cloudier years grapes will not get as ripe, damp and humid years bring rot, a harsh spring frost can cut the yield, and a hailstorm can destroy a crop within minutes (WSET).

• WSET contrasts a cool-climate Chablis, with pronounced acidity, bright citrus flavours and a long finish, against a warm-climate, oak-aged Chardonnay that feels rounder, softer and more buttery
• A dry Trocken Riesling from the Mosel shows bracing acidity, WSET says, while a sweeter Spätlese from the same region can have a similar level of acidity that residual sugar balances
• The University of East Anglia study found that April and May in southern England had become warmer while frost frequency in those months had not changed, and that yields were influenced most by the variability of June rains (Wine Spectator, 2016)
• Jones told Wine Spectator in 2022 that Burgundy made a more elegant, lower-alcohol, lighter-color wine one hundred years ago and that its Pinot Noir has moved from cool-climate limits toward the warmer-climate limits

Primary sources: https://www.wsetglobal.com/knowledge-centre/blog/2026/understanding-acidity-in-wine, https://www.winesofgermany.com/our-regions/growing-area/72/mosel, https://www.winesofgermany.com/our-regions/highlight-of-wine-culture/159/the-bremmer-calmont-vineyard, https://www.nzwine.com/en/media/our-people/brancott/, https://www.nzwine.com/en/regions/marlborough/, https://www.nzwine.com/en/media/story/sauv-blanc-fast-facts/, https://wine.wsu.edu/late-ripening-how-to-deal/, https://www.wsetglobal.com/knowledge-centre/blog/2021/march/22/weather-wine-and-vintages, https://www.wsetglobal.com/knowledge-centre/blog/2024/july/17/understanding-riesling-in-germany, https://www.wsetglobal.com/knowledge-centre/blog/2020/may/01/understanding-grapes-spotlight-on-sauvignon-blanc, https://www.wsetglobal.com/knowledge-centre/blog/2026/strawberry-pepper-and-petrol-why-wine-smells-the-way-it-does, https://www.wsetglobal.com/knowledge-centre/blog/2022/june/21/an-introduction-to-english-wine, https://www.nzwine.com/en/regions/central-otago/. Secondary sources: https://www.guildsomm.com/public_content/features/articles/b/gregory_jones/posts/climate-grapes-and-wine, https://www.winespectator.com/articles/green-talk-wine-climatologist-greg-jones, https://www.winespectator.com/articles/whats-the-future-for-uk-wine-industry-study-finds-climate-change-brings-both-promise-and-risk-52953. Last verified 2026-09-28