Daily Average Temperatures for Bordeaux, Napa, and Albemarle County

Daily Average Temperatures for Bordeaux, Napa, and Albemarle County

Albemarle Terroir is supposed to focus on the terroir of Albemarle County and Charlottesville, VA in an effort to discuss what makes Albemarle Wine unique. The Blog is a platform for me to learn more about the effects of climate on wine and is a great excuse to dive into some climate data.

I’ve discussed papers that explore climate and Bordeaux wine quality, applied it’s concepts to Chateau Montelena vintage notes, and tasted some wine.

I recently read a few papers regarding the potential effects of wine on climate change
and decided it was time to compare the climate in Charlottesville and Albmarle County to Napa Valley and Bordeaux.

The chart above presents the average daily maximum and daily minimum temperatures for Albemarle County (Charlottesville Airport), Bordeaux (the Bordeaux Airport), and for Northern Napa Valley (the St. Helena CIMIS station).

The legend includes:

  1. Bd = Bordeaux (Blue)
  2. Napa = Napa Valley (Red)
  3. Alb = Charlottesville/Albemarle County (Green)

There are a number of weather related risks a vineyard can experience that tend to decrease either the yield of their vines or the quality of the grape juice used to make the wine. They include:

  1. Extremely cold winter temperatures which damage the tissue of the vine
  2. Spring frost damaging the newly grown buds
  3. Excessive heat
  4. Rain during the harvest period
  5. To little rain during winter (the soil does not rebuild is water stores after the dry summer and fall)
  6. Hail

Despite all those risks, temperature is the most important determinant of a regions ability to grown quality grapes for wine production. A wine growing region needs to have a temperature high enough that allows a specific grape variety to grown to maturity during the summer months but not so warm that table grapes or even raisin grapes are produces.

Most people who consume wine on a regular basis have some awareness that the worlds best wines come from Bordeaux and Napa Valley. They may not realize that their climate play a huge role is making them great grape growing regions. The notes below discuss the differences in average temperatures between the three regions and their implications for grape growing.

  1. I was quite surprised at how similar the average daily maximum temperatures between Napa Valley, CA and Albemarle County, Virgina are. The warmest days of the year have a surprisingly similar daily maximum temperature climatology.
  2. Whereas the daily maximums between Albemarle County and Napa are similar, their daily minimum temperatures are not. Napa Valley’s summer time daily minimum temperatures are much lower than Albemarle County’s. This is almost certainly due to a generally drier, less humid Napa climate, allowing for cooler nighttime temperatures.
  3. The Bordeaux daily maximum temperatures during the growing season (the summer period spanning the middle of the graph) are always less than Napa Valley and Albemarle County. However, the daily minimum temperatures are between Napa and Albemarle.
  4. Albemarle County winter time temperatures are substantially lower than Bordeaux and Napa Valley. There is a long answer for why this is the case. The short answer is because Virginia has water to it’s right and a continent to it’s left where and Bordeaux and Napa are the reverse.

There is much more to come on this subject including a comparison of rainfall and extreme temperatures.  This post is the beginning of the exploration of   Albemarle County/Charlottesville  Wine and Climate