Dramatic climate changes occur at Chalone Vineyard not only from season to season but hour to hour. Temperatures can swing from intensely hot during the day (90 degrees F) to considerably cooler at night (50 degrees F) over much of the growing season. Grapes need these cold nights to maintain their acidity while fully developing their flavors. The appellation is dry, with an average rainfall of less than 15 inches annually, and Climatological Data Reports from the US. Weather Bureau classify the Chalone appellation as Region I in some years and Region IV in others. Despite such variation, Chalone sees very little difference in wine quality from year to year, and therefore feels that the unique character of their wines is not based on weather, but on the unique soils in which the grapes are grown.
