Metropolitan City of Cagliari the warmest month with an average temperature of that of about . African anticyclone activity can cause heat waves starting in June. From mid-June to mid-September rain is rare and appears in afternoon storms. The rainy season starts in September, but the first cold days come in December, usually the wettest month. Winds are frequent, especially the mistral and sirocco; in Summer days a marine sirocco breeze ("s'imbattu") lowers the temperature and the humidity. On the surrounding mountains, the climate is very different with plentiful average rainfall, cold winters, and mild warm summers (Csb in the Köppen climate classification). As
Sirocco the low propels the mixed air across the southern coasts of Europe. The sirocco causes dusty dry conditions along the northern coast of Africa, storms in the Mediterranean Sea, and cool wet weather in Europe. The sirocco's duration may be as short as half a day or may last several days. While passing over the Mediterranean Sea, the sirocco picks up moisture; this results in rainfall in the southern part of Italy, known locally as "blood rain" due to the red sand mixed with the falling rain. Many people attribute health problems to the sirocco, either because of the heat