Equinox and Solstice What are they and why are they important to us?
Earth rotates (spins) on its axis at a tilt of 23.5 degrees. It takes 24 hours to make a whole rotation (purple arrows). • Earth revolves (goes around) the sun. It takes 365 days to make a whole revolution (red arrows).
Notice how being tilted on an axis makes the northern hemisphere of the Earth get more sun than the southern during the months of July, August and September—we call that summer. The days are longer and the nights are shorter, creating a warmer temperature for that time. In the southern hemisphere, it is winter. The longest day of the year in the north is June 21—we call it the summer solstice. The north pole gets 24 hours of daylight and the south pole gets 0 hours of daylight during our summer solstice.
Notice how being tilted on an axis makes the northern hemisphere of the Earth get less sun than the southern during the months of January, February, and March—we call that winter in the northern hemisphere. The nights are longer and the days are shorter, creating a colder temperature for that time. In the southern hemisphere, it is summer. The shortest day of the year in the north is December 21—we call it the winter solstice. The south pole gets 24 hours of daylight and the north pole gets 0 hours of daylight during our winter solstice.
There are two days in the year when the day and night are exactly equal in both the northern and southern hemisphere. They occur September 21 and March 21. We call those fall equinox and spring equinox. Every one in the world experiences 12 hours of daylight and 12 hours of night.
It is the tilt of the Earth that causes the seasons. Without it, we would have consistent temperatures all year. This impacts our weather, climate, ability to grow crops, live in certain areas, and enjoy the activities in each of the seasons. Watch this simulation: Geography seasons
Some people think that on the days of the equinox, you should be able to balance an egg on its end. What do you think? World record, egg balancing—1290 eggs! (not all pictured)