The climate of Milan is Mediterranean, but like any large urban metropolis, buildings and human activity affect the local micro-climate. In the case of Milan this makes the weather rather more extreme. Summers can be hot and humid, with temperatures rising above 86°F (30°C) during August. The mountains behind the city protect Milan somewhat from the severity of winter, but the weather is very chilly with temperatures occasionally dropping below freezing. Winter also brings rain showers and heavy fog. Spring (March to May) and early summer (June) are the best time to visit Milan weather-wise, although autumn (September to November) is also pleasant. In late summer, particularly August, it gets uncomfortably hot and many locals depart for their summer break, leaving some restaurants and hotels closed. Winter is a bit cold for most tourists but Milan's attractions are world-class during any season. Milan has a busy event calendar and unless you are travelling particularly to attend a big festival it is best to avoid international events like Milan Fashion Week, because the city gets crowded and more expensive. Essentially Milan is a year-round tourist destination.