Winter

Winter is the coldest season of the year, between autumn and spring, marked by the shortest days and longest nights.

Meteorological winter is the season having the shortest days and the lowest average temperatures, which have the coldest weather.This corresponds to the months of December, January and February in the Northern Hemisphere, and June, July and August in the Southern Hemisphere. The coldest average temperatures of the season are typically experienced in January in the Northern hemisphere and in June or July in the Southern hemisphere.

Nighttime predominates the winter season, and in some regions it has the highest rate of precipitation as well as prolonged dampness because of permanent snow cover or high precipitation rates coupled with low temperatures, precluding evaporation. Blizzards often develop and cause many transportation delays. A rare meteorological phenomenon encountered during winter is ice fog, which comprises ice crystals suspended in the air; it occurs only at very low temperatures, below about –30°C.

Source: en.wikipedia.org/wiki/Winter - 04.08.2010