During one part of the Earth’s orbit the northern hemisphere will be tilted towards the Sun and six months later the other hemisphere will be. When the tilt of the Earth’s axis causes a hemisphere to tilt towards the Sun, the Sun will appear higher in the daytime sky in that hemisphere.
The animation below shows how the position of the midday Sun changes with the seasons. |
What difference does a high or low Sun make to things?
When the Sun is low (15° above the horizon) at midday, sunlight is spread over a large area of the Earth's surface. The area is nearly 3.5 times as big as that which is covered when the Sun is at an angle of 62°. In winter, therefore, the effect of sunlight on the Earth’s surface and atmosphere is reduced and it is much less able to heat them. Perhaps it's not surprising then that summer days are warmer than winter days!
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