Cru to benefit from a particular terroir, even more differentiated by the climate. Climatology On the western side, the Vosges Mountains shield the Alsatian vineyards from wind and rain. Predominately western winds lose their moisture on the eastern side of the Vosges and arrive as Foehn winds into the Alsace plain. The precipitation mean in Alsace is the least of all French wine regions. Colmar is one of the driest cities in France. Consequently, the climate is more temperate than expected at this latitude: the annual mean temperature is about 1.5 °C higher. The climate is semi-continental and dry with hot springs, sunny and dry summers, long autumns and cold winters. Each of the Grands Crus benefits from a microclimate, inevitably different from place to place. Allowed varieties As of 2011, Alsace Grand Cru wines can only be produced using one of four white grape varieties: Riesling, Muscat, Pinot gris and Gewürztraminer. In 2006, Zotzenberg became the only Grand Cru vineyard that could produce wine from Sylvaner. Except for certain vineyards where blends are allowed, the wines must be exclusively made using a single variety and may be labelled as such. Late harvest wines must be labelled by grape variety. For Muscat-labelled wines, only one of the allowed Muscat varieties can be used (see table below). Vineyards where blends are allowed In some Grand Cru vineyards, blends are allowed, which may also include some non-noble grapes. In Alsace, blends have usually been associated with wines of lesser quality. The producer primarily associated with high-quality blends is Marcel Deiss. List of Alsace Grands Crus Grand Cru vineyards (lieux-dits) with their commune(s)/village(s), département, size and the date it was granted Grand Cru status. Where the same name is used for several vineyards, its official name is "vineyard" de "village", such as Altenberg de Bergbieten, Altenberg de Bergheim or Altenberg de Wolxheim. See also Alsace wine regions Alsace wine References External links Alsace Grand Cru on the Official Alsace wines site , linking to PDF-documents on each Grand Cru, retrieved 2011-04-22. The Grand Cru system of Alsace and Sortable list of Alsace Grand Cru on alsace-wine.net , retrieved 2011-04-22. Alsace wine AOCs