Bishkek has a Mediterranean-influenced humid continental climate (Köppen climate classification ''Dsa''.), as the average mean temperature in the winter is below . Average precipitation is around  per year. Average daily high temperatures range from  in January to about  during July. The summer months are dominated by dry periods, punctuated by the occasional thunderstorm, which produces strong gusty winds and rare dust storms. The mountains to the south provide a natural boundary and protection from damaging weather, as does the smaller mountain chain that runs north-west to south-east. In the winter months, sparse snow storms and frequent heavy fog are the dominating features. There are sometimes temperature inversions, during which the fog can last for days at a time.