VEI (Vintage Evaluator Index)
The VEI is a quantitative proprietary indicator/tool developed to evaluate mathematically a vintage from a specific wine region, relative to its most recent 30-year period available climatological normals.
The VEI is a combination of two different indicators: one computes the monthly temperatures that occurred in a specific year; the other calculates the amount of monthly precipitation accumulated in the same year. Then the two indicators are combined in a way to reflect the potential of that year’s vintage.
The same process is carried out for the climatological normals monthly data (temperature & precipitation). To this the result is attributed the value of 100. Therefore, if we obtain an index number for VEI above 100, we know that this is a warmer than normal vintage, and consequently, there is a higher potential for grape physiological maturation.
For cold regions like Bordeaux, a VEI reading above 100 means a good vintage, or at least, better than average. For hotter regions like Napa Valley, readings bellow 100 may imply that the vintage will produce more elegant wines.
[1] Data in black – from months which do not belong to the growing season, and subsequently, not computed in the VEI (Vintage Evaluator Index) algorithm – represents, most of the times, climatological normals data.
[2] Data in red is also climatological normals data.
[3] The meteorological stations representing the studied wine regions are chosen among the best proxies, according to the availability and integrity of its data.