At the equator, the temperature variation is much smaller throughout the year, and it is common to consider just two seasons: dry and wet or monsoon. For observers right at the north pole and the south pole, there are only two seasons — an almost six-month long winter night followed by an almost six-month long summer day!
Within the Arctic circle and the Antarctic Circle latitudes The date of the start of the seasons is often chosen to start on the dates of the solstices summer and winter and equinoxes autumn and spring. Only a few parts of the world experience the classic four seasons of spring, summer, autumn and winter. Many parts of the world get only two or even one.
So, what's going on? But our planet isn't perfectly upright when it spins. Thanks to a few collisions during its formation, the Earth is tilted at an angle of This means that as the Earth takes it annual trip around the Sun, different areas of the planet face the Sun more directly during their daylight hours at different times of the year. The tilt also affects the daily amount of light — without it the whole planet would have hour days and nights every day of the year.
Australia has summer at the end of the year when the southern hemisphere is tilted towards the Sun. In summer, days are longer because more hours are spent facing the Sun. And they're hotter because we're facing the Sun more head-on — so we get hit by more rays of sunlight than if we were on an angle. The summer solstice in Australia — about December 22 — is when we have our longest day of the year. On this day the Sun is as far south in the sky as it gets — it passes directly above the Tropic of Capricorn, roughly over Rockhampton.
But while we're busy planning Christmas barbecues, the northern hemisphere is tilted away from the Sun. That means there are fewer daylight hours up there and the light is spread out over a greater surface area, so it doesn't get as warm. Their shortest day — the winter solstice — happens on our longest. The tables turn six months later, when the Earth is halfway around its orbit of the Sun. It is winter in December in the Northern Hemisphere, because that is when it is the South Pole's turn to be tilted toward the Sun.
And, believe it or not, aphelion when Earth is farthest from the Sun occurs in July, and perihelion when we are closest occurs in January.
For those of us who live in the Northern Hemisphere where it's summer in July and winter in January, that seems backwards, doesn't it? That just goes to prove that Earth's distance from the Sun is not the cause of the seasons.
What Causes the Seasons? The Short Answer:. Earth's tilted axis causes the seasons. Notify me of new posts by email. This site uses Akismet to reduce spam. Learn how your comment data is processed. Winter is actually my favorite season, but these summer locations I never would have thought of except Hawaii, because every American thinks Hawaii.
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