The Northern Hemisphere, the northern half of the earth, has winter weather during December, January, February, and early March. In the Southern Hemisphere, winter weather begins in late June and lasts until early September. During winter, the polar regions are especially cold because the sun does not rise there for weeks or months at a time. The lowest winter temperatures usually occur in the middle of all continents. In the Northern Hemisphere, cold, dry air moves south from the North Pole, bringing cold weather.
Storms move from west to east along the southern edge of the cold air.
In the United States, winter storms produce large snowfalls in some areas. The most snow falls in the western mountains and in much of the northern region east of the Rocky Mountains. Many winter storms bring rain to warmer southern areas. For a demonstration, click here . All rights reserved.