Why do we have seasons on earth?

During part of the year, Earth is closer to the sun than at other times. However, in the Northern Hemisphere, we are having winter when Earth is closest to the sun and summer when it is farthest away! Earth has seasons because its axis doesn't stand up straight. read more

Long, long ago, when Earth was young, it is thought that something big hit Earth and knocked it off-kilter. read more

Explore what causes seasons on Earth in this interactive produced by WGBH and adapted from NASA materials. The interactive features four cities at different latitudes (New York City, Miami, Singapore, and Melbourne) and provides information about their seasonal conditions at eight points in Earth's orbit. read more

When the earth's axis points towards the sun, it is summer for that hemisphere. When the earth's axis points away, winter can be expected. Since the tilt of the axis is 23 1/2 degrees, the North Pole never points directly at the Sun, but on the summer solstice it points as close as it can, and on the winter solstice as far as it can. read more