Our year has four parts. The parts are called seasons. Each season has its own weather. Winter is usually the coldest season. Winter in the Northern Hemisphere starts in the month of December. South of the equator, the seasons are reversed. Our winter is their summer. Our summer is their winter. Some people think that Earth is farther away from the sun in winter. That is not true. The Earth is really closer to the sun in winter than in summer! Seasons are caused by the tilt of Earth's axis. When the Northern .....