Washington State Terroir

Washington State

Perfect climate for growing grapes

The Sun

Great wine grapes need the sun to aid in the production of sugars (via photosynthesis), color development and heat accumulation for overall flavor and structure ripening. How much sun does Eastern Washington receive?

  • While the growing season is slightly shorter from beginning to end than more southerly wine regions, the number of sun hours received in Eastern Washington is equal due to incredibly long days at our northern latitude – receiving up to 17 and a half hours of sun each day.
  • There are NO clouds 300 days of the year.
  • Long days and lack of clouds result in “high light intensity”, a must for great photosynthesis.
  • The longer day length is similar to the great wine regions of Northern Europe, as they share similar latitudes.

Dry Growing Season

Eastern Washington is one of the most northern wine regions in the world. Similar areas elsewhere tend to be on the cusp of cool, rainy weather in the spring and fall, making viticulture difficult – especially at sensitive times like harvest. Eastern Washington is dry enough to be categorized as a Continental Semi-Desert. Why?

  • The majestic north-south running Olympic and Cascade Mountain ranges in the Western portion of Washington combine to stop the clouds rolling in from the Pacific Ocean, creating a Rain Shadow Effect. Eastern Washington is the most northern latitude wine region to experience this phenomenon in the New World (read: not Europe).
  • Only 7 to 12 inches of rain fall annually in Eastern Washington.
  • Common vineyard fungal diseases such as oidium (powdery mildew), peronospera (downy mildew) and grey/black rot require a humid environment. Due to its arid climate, Eastern Washington is remarkably pest and disease free; as a result, very few chemical-based fungicides are required, leading to sustainable vineyard practices that leave vibrant, healthy, lively soils and water sources.

The Water

Eastern Washington has the good fortune of having incredible water sources to rely on for irrigation in such an arid region. This allows absolute control as to when the vine is given moisture and how much is given, which contributes to grape ripeness, lack of sugar dilution, canopy management and dehydration controls at vital moments during its growth.

  • Mountain Rivers: The Columbia Basin benefits from snowmelt runoff. The massive Columbia River in Eastern Washington is the most obvious example, combining the Cascades, Rockies and Blue Mountains runoff to the 15th largest river in the United States at 1,214 miles in length.
  • Underground aquifers run through levels of the basalt lava flow and can be tapped via wells for water reservoirs. World-class, technologically controlled/timed irrigation systems are utilized to influence the growth of many vineyards.
  • Drip irrigation is most common, but some overhead spray irrigation also exists.

Daytime Air and Soil Temperature

Consistently warm daytime air and soil temperatures during the growing season are critical to producing the grape varieties that Washington State specializes in, helping with the physiological ripening – including skin color, skin and pulp texture, seed color and texture, tannins and other flavor compounds. Cold (though not freezing – see “Vital Issues” at the end of this section) during the winter months are ideal for vine dormancy, allowing the plant to rest and restore.

  • Average daytime high vineyard air temperatures for June 1 to October 15: 78 degrees Fahrenheit. During the all-important August/September months, that average climbs slightly higher to 84 degrees Fahrenheit.
  • Average daytime high temperatures for December 1 to March 1: 32 degrees Fahrenheit.
  • In addition to allowing proper dormancy, these cold winter temperatures kill many vineyard disease-carrying pests such as phylloxera, moths, mites, and nematodes. This makes Washington vineyards remarkably pest-free. As a result, very few chemical-based pesticides are required, leading to sustainable vineyard practices that leave vibrant, healthy, lively soils and water sources.