I learned in school that seasonality is due to the earth’s tilt. Summer (in which hemisphere you live in) is hot because the sun shines on your part of the earth for more hours than it does in winter. Makes sense, but how does the UV Index work? I’ve been checking it recently and a hour of sunshine at this time of the year is much more damaging than other times. IDK if it’s in my mind but sunshine on my skin just feels… “burnier.” Presumably the amount of radiation the sun puts out doesn’t vary with seasons. It is also due to angle? Is it something with heat? Am I imagining this?
In: Planetary Science
>Summer (in which hemisphere you live in) is hot because the sun shines on your part of the earth for more hours than it does in winter. Makes sense, but how does the UV Index work?
So this understanding of summer is actually incorrect. For example the north pole gets 24/7 sunlight during the summer but is still colder than the equator which gets 12 hours of sunlight year round.
The actual reason for summer is, as you said, the tilt of the planet. During summer your hemisphere is tilted towards the sun. This means that more sunlight per square mile is hitting your hemisphere so it gets noticeable hotter than it does during the winter.
And since sunlight is more concentrated during summer the UV Ray’s in sunlight are also more concentrated.
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