Explore the Seasons
Why do we have seasons?
Goal:
Goal:
As Earth makes its annual journey around the sun, we experience changes in climate. We call these changes seasons. There are four major seasons on Earth: spring, summer, autumn, and winter. Click the arrows below to find out more.
You might think that the changes in Earth's seasons relate to the distance of Earth from the sun. But that's not true! The real reason for the seasons is the tilt of Earth's axis.
As Earth travels around the sun every year, the North Pole points toward the sun around June 21. This marks the beginning of summer in the Northern Hemisphere. This day has the longest period of daylight and the shortest period of darkness of any day of the year. This day, on or around June 21st, is called the summer solstice. On this day, the path the sun traces in the sky is at its highest point.
As Earth continues on its orbit around the sun, the days gradually become shorter and the nights become longer. By September 22, neither of the poles point toward the sun. On this day, the sun at noon is directly overhead if you are standing on the equator. Every place on Earth will have 12 hours of sunlight and 12 hours of darkness. This day is called the autumnal equinox.
After the autumnal equinox, daylight hours continue to decrease in the Northern Hemisphere. The winter solstice, when the North Pole is pointed away from the sun, falls on or around December 21. It's the day of least sunlight and longest nighttime in the Northern Hemisphere. On this day, the sun's path is lowest in the sky.
Each day after the winter solstice, the sun's path creeps higher in the sky in the Northern Hemisphere. Days begin to get longer until the vernal equinox on or around March 21. This day marks the beginning of spring in the Northern Hemisphere. As with the autumnal equinox, the entire Earth experiences 12 equal hours of day and night on this date.
