Loudoun Weather vs Bordeaux Weather
Before reading further, please note that I have not done any long term sort of study on weather patters in Loudoun County and I am no expert on how these patterns affect vine production, but we have to start somewhere, right :). The weather data below is all from IAD (Dulles Airport) which is about 15 miles from the closest vineyard, but it is the most reliable publicly available weather source I could locate.
| Month | IAD Temp | IAD Avg Temp | IAD Rain | IAD Avg Rain |
| May | 65 F | 62.3 F | 10.26 In | 4.22 In |
| June | 73.1 F | 70.9 F | 6.69 In | 4.7 In |
| July | 74.9 F | 75.7 F | 2.18 In | 3.57 In |
| August | 79.3 F | 74.3 F | 2.75 In | 4.7 In |
Now, compare those numbers to the converted Bordeaux numbers:
| Month | IAD Temp | BOD Temp | IAD Rain | BOD Rain |
| May | 65 F | 63.14 F | 10.26 In | 3.07 In |
| June | 73.1 F | 68.53 F | 6.69 In | 2.95 In |
| July | 74.9 F | 70.7 F | 2.18 In | 1.81 In |
| August | 79.3 F | 72.68 F | 2.75 In | 0.787 In |
It appears Loudoun is hotter and wetter than Bordeaux, but this still doesn't tell us much about Loudoun's 2009 vintage. To do that let's compare the numbers to 2007, which a lot of winemakers have told me was one of the best vintages in Loudoun history:
| Month | 07 IAD Temp | 09 IAD Temp | 07 IAD Rain | 09 IAD Rain |
| May | 65 F | 66.1 F | 0.34 In | 3.07 In |
| June | 73.1 F | 74.4 F | 6.69 In | 2.92 In |
| July | 74.9 F | 77.3 F | 2.18 In | 1.75 In |
| August | 79.3 F | 74.3 F | 2.75 In | 1.67 In |
In this comparison, we see that 2007 was hotter and much drier than 2009. This doesn't mean 2009 is going to be a bad vintage, not at all. But, now that we have a baseline it will be fun to see how these weather patterns affect the fruit and ultimately, the wine.







