I’ve recently discussed several interesting weather/climate and wine related issues. In particular, a recent compared the daily maximum and minimum temperature climate of Napa Valley, Bordeaux, and Albemarle county. As discussed in a recent Charlottesville Daily Progress article, one of the major differences of growing wine in Albemarle County and surrounding regions is the effect of heat and humidity on grapes. To explore the heat element a bit further, this post will look in a bit more detail at the maximum temperature climatology.

In the chart below I show several types of data for Napa, Bordeaux, and Albemarle.

A comparision of Maximum Temperatures

1) The thick lines have the same color coding as my previous post comparing climates in Napa, Bordeaux, and Albemarle and is identical to the average maximum daily temperature shown in that post.

2) The thin lines (labeled “Max”) are the highest maximum temperature ever recorded for a given day in each of the three regions.

3) The thin lines near the bottom of the graph depict the standard deviation of maximum temperature for each day of the year.

The standard deviation calculations indicate that, generally speaking, the standard deviation of daily maximum temperature during the summer growing season are all approximately the same. The Albemarle County standard deviations are generally larger during winter months. Interestingly, this is also true for daily minimum temperatures suggesting the risk of tissue damage due to severe cold temperatures in Albemarle county is greater than in Bordeaux and Napa Valley.

The risk of extreme temperatures, as measured by the highest recorded daily maximum temperatures is highest in Napa Valley. So, despite the average daily maximum temperatures climatology between Albemarle and Napa Valley being approximately the same, the risk of severe temperature extremes is much greater in Napa Valley.

Up next, discussion of the effect of heat damage.