average of Milan's area is in the period between 1961 and 1990, with a record of in January 1985. In the suburbs the average can reach . The city receives on average seven days of snow per year. The city was often shrouded in thick cloud or fog during winter, although the removal of rice paddies from the southern neighbourhoods and the urban heat island effect have greatly reduced this occurrence since the turn of the 21st century. Occasionally, the Foehn winds cause the temperatures to rise unexpectedly: on 22 January 2012 the daily high reached while on 22 February 2012 it reached . Air pollution levels rise significantly in wintertime when cold air clings to the soil, causing Milan to be one of Europe's most polluted cities. Summers in Milan are hot and humidity levels are high with peak temperatures reaching above . Due to the high humidity, urban heat effect and lack of wind, nighttimes often remain muggy during the summer months. Usually the summer enjoys clearer skies with an average of more than 13 hours of daylight: when precipitation occurs though, it is more likely to be accompanied by thunderstorms and hail. Springs and autumns are generally pleasant, with temperatures ranging between ; these seasons are characterized by higher rainfall, especially in April and May. Relative humidity typically ranges between 45% (comfortable) and 95% (very humid) throughout the year, rarely dropping below 27% (dry) and reaching as high as 100%. Wind is generally absent: over the course of the year typical wind speeds vary from (calm to gentle breeze), rarely exceeding (fresh breeze), except during summer thunderstorms when winds can blow strong. In the spring, gale-force windstorms may happen, generated either by Tramontane blowing from the Alps or by Bora-like winds from the north. Due to its geographic location surrounded by mountains on 3 sides, Milan is among the least windy cities in Europe. Administration Municipal government The legislative body of the Italian is the City Council (Consiglio Comunale), which in cities with more than one million population is composed by 48 councillors elected every five years with a proportional system, at the same time of the mayoral elections. The executive body is the City Committee (Giunta Comunale), composed by 12 assessors, that is nominated and presided over by a directly elected Mayor. The current mayor of Milan is Giuseppe Sala, an independent leading a centre-left alliance