Near the outer limits of the viticulture area, the Rías Baixas Appellation of Origin (DO) is fully integrated into the great Atlantic region whose boundary is Wagner’s line (Wagner P., 1976). These DO wines are, therefore, Atlantic wines.
In Winter, the Atlantic storms approaching from the West and Southwest, with their associated warm fronts -oftentimes composed of tropical air- bring heavy rains, which make for mild to warm temperatures with little variation between day and night. Storms from the North and Northwest occur less frequently and by the time they reach the area, they have weakened and bring little rainfall. It is only the invasion of cold Arctic air or the periods when the high pressure areas sweep the stormy fronts north that night temperatures may drop low enough to cause freezing.
To get an idea of how mild the winters are, consider the mean temperature during January –the coldest month of the year- which ranges from 10 degrees in A Guarda to 9 degrees in Frieira. As far as precipitation is concerned, this season is extremely rainy, with the average annual rainfall ranging from 600 mm de to 1600 mm in winter.
Spring comes early and with it more showers. The climate-related dangers during this season are damage from frost and impaired flowering. There is no danger of frost on the coast but the chances of freezing temperatures increase as we move inland. The extent of frost damage depends heavily upon the irregular orography typical of the Rías Baixas DO.
High pressure areas from the Azores settle over the western Atlantic in early summer, preventing the passage of atmospheric disturbances, which, at most, blow across the northern boundary of Galicia.
Rainfall is infrequent and light during this season and the temperatures remain mild thanks to the fresh air. Summer storms are rare, but with a risk of hail. The summer season dries out the soil, favoured by a drop in rainfall, higher temperatures and sandy soils that facilitate infiltration.
Once the high pressure areas move on, the storms begin, one after another, during the Autumn season, again marked by heavy rainfall.