In 1967 Andre Simon, the prominent wine writer, predicted that the 1965 Bordeaux would be as good as the promising 1961 vintage. Today, few of the weak, acidic 1965's are available. One that is, Chateau Lafite-Rothschild, sells at auction for just one-fifteenth the price of the truly great 1961 wines from the same vineyards.

Mr. Ashenfelter, a 47-year-old specialist in labor economics who is the managing editor of The American Economic Review, is convinced he has found a better way.

It is widely agreed that weather influences wine quality. What few understand, he argues, is that a mere handful of facts about the local weather tell almost all there is to know about a vintage. And using the same techniques employed to forecast, say, the effect of a change in wage rates on employment in the auto industry, he has gone a long way toward proving his audacious theory.

It's Laptop vs. Nose

Weather-based vintage prediction is not a new idea. What is new is the notion that laptop computers can outperform the most sophisticated noses and palates.

The critical concept, Professor Ashenfelter acknowledges, came from Bruno Prats, owner of Chateau Cos d'Estournel in the St.-Estephe region of Bordeaux. Mr. Prats charted both the average temperature during the growing season and rainfall during the harvest months to make systematic comparisons between vintages.

Professor Ashenfelter added data for winter rainfall and then rigorously measured their statistical relationships to the most objective measure of quality he could devise: an index of auction prices for about 80 wines after they have matured in the bottle.

According to this ''multivariate regression analysis,'' heavy rains in the winter followed by a hot summer improve wine quality, while rainfall before the harvest damages it. The statistical fit from 1952 through 1980 is remarkably snug for the red wines of Burgundy as well as Bordeaux.