The hills of Montalcino, having been formed in differente geological eras, present extremely variable soil characteristics, in both constitution and structure. The lowest areas consist of terrain created by the deposit of allubial material with an active stratum that is deep and quite loose, dating from the Quaternary Period. Further uphill, the terrain, enriched by fossil material, has a layer of soil formed by the decomposition of ancient rock, especially marl and limestone. The terrains are moderately sandy, rich in lime, mingled with areas of volcanic soil, but tending to be thin.
The climate is typically Mediterranean with precipitation concentrated in the months of May, October and November. In winter, snow is found above an altitude of 400 meters. Monte Amiata (1,700 meter) to the southeast represents a natural barrier that protects Montalcino from most climatic adversities such as sudden downpours and hail-storms. The strip of the hill of moderate altitude, where the greater part of the winemaking estates are situated, is not affected by fog, ice or late frost as are the surrounding valleys, while the normal, persistent winds ensure the best conditions for the health of the plants.
The fundamentally mild climate and the large number of days of serene weather during the entire vegetative cycle ensure the gradual and complete ripening of the grape clusters. The existence in the territory of slopes with different orientations, the pronounced modulations of the hills and the disparity between the low-lying areas and the higher districts, produce micro-climates that are diverse despite the relative compactness of the area.