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.
Each monthly result (temperature & precipitation), as well as the final Vintage Evaluator Index (VEI) result, are then divided by the average temperature and precipitation volume from the last available climatological normal and normalized to the base 100. To the climatological normals it is attributed a value of 100.
Consequently, if we obtain an index number for the VEI above 100, we will know that this one was a warmer than normal vintage, with a higher potential for grape physiological maturation.
For cool regions like Bordeaux, a VEI reading above 100 means a good vintage, or at least, better than average. For warmer regions like the Napa Valley, readings bellow 100 may imply that the vintage would yield subtler, 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.