Behold Summer...
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The sun rises around 4 or 5am. The sun reaches its highest point at noon. The sun is in middle points between 8am and 9am and then again from 4pm to 5pm. The sun sets around 9 or 10pm.
Now Behold Winter...
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The sun rises around 8am and sets around 4 or 5pm. The sun reaches its highest point at noon, but wait...
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The sun at noon in the winter is at the same position it would be around 8am or 4pm in the summer. Therefore the sun never reaches center sky, it clings near the southern horizon throughout the day! That means we are getting less light and therefore less warmth!