Climatic change estimated by fluctuations in the date of eastern European grape harvest. Early harvest indicates warm-dry (peaks in the chart). Late harvest indicates cold-wet summer (troughs).
Fig. IV Sakulare Schwankungen des Termins der Weinernte, In wie weit ist das heutige klima konstant, Eduard Bruckner, p119 Verhandlungen des VIII, Deutschen Geographentages, Berlin, 1889. Dates of the beginning of the grape harvest in France, Sourthwest Germany and Switzerland. ‘It is common knowledge that grapes tend to mature late during cool, wet years and early in dry, warm years.’ Units of days deviations from 30 year mean of 1851-80.
