by: rebekah niemann
What causes Winter?
Winter in either the Northern Hemisphere or the Southern Hemisphere is caused by the axis of the Earth in that hemisphere being oriented away from the Sun. Different cultures define different dates as the start of winter, and some use a definition based on weather, but when it is winter in the Northern Hemisphere it is summer in the Southern Hemisphere, and vice versa. In many regions, winter is associated with snow and freezing temperatures.
found on http://en.wikipedia.org/wiki/Winter