Montalcino: Climate: Guelfo Magrini (2003, p.24-25) describes Montalcino’s climate as typically Mediterranean, with rainfall concentrated mainly in the spring and autumn, averaging 690-700mm (27.1-27.5 inches) annually. Months with the highest levels of rainfall are May, October and November. In winter snow above 40 metres (131 feet) is not infrequent (Magrini, ibid). The climate is mild, with over 160 sunny days annually.
Hillside areas rarely experience freezing, late frost, or fog (although see the Canalicchio area). The variations in aspect and topography provide constant airflow which reduces the risk of vine diseases. The vineyards to the north west are cooler, those to the south (Camigliano, Tavernelle, Sant’Angelo, Castelnuovo dell’Abate) are more influenced by the warm winds blowing across the Maremma from the Tyrrhenian Sea. Overall, Montalcino is warmer and drier than the Chianti Classico DOCG region to the north which gets little direct moderating influence from the Tyrrhenian. This is reflected in Montalcino’s flora (see below), particularly the presence of mastic and Indian fig, and partly explains why unlike Chianti Classico DOCG or Vino Nobile, Brunello di Montalcino can and must be 100 per cent Sangiovese (‘Sangiovese in purezza’).
Guelfo Magrini (2003) Brunello di Montalcino by Guelfo Magrini (Morganti Editori, 2003), English edition.