It's Spring!

It's Spring!

Why do we have seasons?

The vernal - or spring - equinox marks the start of spring in the northern hemisphere. This year - 2012 - the spring equinox was on March 20.

Why does the equinox happen?

The equinoxes - and our seasons - are caused by the Earth orbiting the Sun and the Earth's tilt.

The Earth is tilted 23.5 degrees on its vertical axis. During the northern hemisphere's spring and summer, the northern hemisphere is tilted towards the Sun.

During the northern hemisphere's autumn and winter, the northern hemisphere is tilted away from the Sun.

During the spring and autumn equinoxes, the Earth is neither tilted towards or away from the Sun.

This means that both the northern and southern hemispheres receive equal sunlight. Hours of daylight and night are roughly equal.

Curriculum information