Lisa Buxbaum, age 8, of Huntsville, Alabama, for her question:

What makes the weather turn cold?

The weather happens in the air above the ground, all around the whole world. And all around our big globe, the weathery air is always moving. It moves from here to there and hates to stay very long in one place. The weather we get today came from somewhere else. A storm may blow in from any direction. But the world has special winds that blow most of the weather along certain paths. They blow most of our warm and cool spells from the west.

When a huge pocket of air blows over a hot desert, it gets warm. The wind blows it along and it brings us a spell of warm weather. When a huge pocket of air sits on the frozen North Pole, naturally it gets cold. Sooner or later it has to spread out and move away. The winds carry the pocket of chilly air on its way. As it goes, it brings a spell of cold weather to all the places along its path. Our cold spells and winter storms are born in the frozen north. They push southward. As a rule, the westerly winds carry them overhead, toward the east.