ElI5: Why do different places on the earth receive different annual sunlight hours?

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Just saw a post talking about how Europe gets a decent amount of sunlight less than the Americas. Why would this be? I understand the how latitude changes the time of sunrise/sundown but wouldn’t it average out in the end? For example Alaska vs. Hawaii. Hawaii gets close to 12 hrs of sunlight every single day all year. Alaska might get 22 some days in the summer but 2 in the winter? Wouldn’t both places receive the same annual hours of sunlight or am I missing something?

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Anonymous 0 Comments

You are correct: on an annual basis, anyplace on the should receive exactly the same hours of light as any other. ( This is only true if the globe is a perfect sphere, not being ovoid, nor having mountains and valleys. In practice, the earth is close enough. )

However, the total amount of energy is quite a bit less. Europe is further north, and the angle of the light decreases the energy received in two ways: the sunlight has to go through more atmosphere to get to the surface, and the area that the sunlight hits is larger. ( FWIW, the energy received is proportional to the cosine of the angle between the sunlight and vertical )

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