Snowfalls tend to be heavy, but the snowcover and temperatures below the freezing point rarely last more than a few days. Spring and autumn are mild, but are unpredictable and often wet, and can range from chilly to warm, however the nights are chilly.
Istanbul has a persistently high humidity, which can exacerbate the moderate summer heat. The humidity is especially salient during the morning hours, when humidity generally reaches eighty percent and fog is very common. The city receives fog an average of 228 days each year, with the highest concentration of foggy days being in the winter months, although it usually dissipates by noontime. Thunderstorms are uncommon, occurring just 23 days each year, but they occur most frequently in the summer and early autumn months. Istanbul has an annual average of 124 days with significant precipitation, which together generate around 844 mm (33 in) of rain. The highest recorded temperature was 40.5 °C (105 °F) on 12 July 2000, and the lowest recorded temperature was 16.1 °C (3 °F) on 9 February 1927.[74] Istanbul also tends to be a windy city, having an average wind speed of 18 km/h (11 mph).Due to the city's huge size, topography and maritime influences, Istanbul exhibits a multitude of distinct microclimates.
Levent financial district in winter.