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General Science => General Science => Topic started by: alexsunny123 on 20/10/2020 11:28:25

Title: The amount of daylight in summer and winter?..
Post by: alexsunny123 on 20/10/2020 11:28:25
Hello,

Why is there the same amount of daylight in summer as there is in winter?


thanks
alexsunny
Title: Re: The amount of daylight in summer and winter?..
Post by: Bored chemist on 20/10/2020 12:28:37
There isn't.
Title: Re: The amount of daylight in summer and winter?..
Post by: pensador on 20/10/2020 13:52:24
There isn't.

At the equator the day length is almost the same all year round. As you approach the poles seasonal fluctuations are more noticeable.

Perhaps the OP lives near the equator.
Title: Re: The amount of daylight in summer and winter?..
Post by: alancalverd on 20/10/2020 13:57:23
But "summer" and "winter" are meaningless at the equator.
Title: Re: The amount of daylight in summer and winter?..
Post by: chiralSPO on 20/10/2020 16:54:15
There isn't the same amount *locally*.

But the Earth gets essentially the same amount of insolation from the sun, no matter the season (modest eccentricity of our orbit means there is some variation over the course of the year which will systematically mean that during one "season" the Earth is closer than in other seasons, but my understanding is that there are even longer cycles for which that bias shifts around the year too).
Title: Re: The amount of daylight in summer and winter?..
Post by: evan_au on 20/10/2020 21:46:29
This map illustrates how much day and night the world gets on 4th January.
- Look horizontally at your latitude, and see how much of it is dark (night), and how much is light (daytime)
- This indicates the relative hours of night and day as the Earth rotates
- In January, the northern hemisphere gets less daylight and more night
- In January, the southern hemisphere gets more daylight and less night (yippee! it's summer!)
- As Bored Chemist ChiralSPO says, the total is roughly the same over a year all year round.
- 4th January is when the Earth is closest to the Sun (perihelion), which makes the sunlight slightly more intense, but does not affect the hours of sunlight very much.
See: https://www.timeanddate.com/worldclock/sunearth.html?iso=20210104T2038
Title: Re: The amount of daylight in summer and winter?..
Post by: Bored chemist on 20/10/2020 22:24:31
As Bored Chemist says, the total is roughly the same all year round.
That's more or less the opposite of what I said.
Title: Re: The amount of daylight in summer and winter?..
Post by: alancalverd on 20/10/2020 23:00:59
Ah, statistics!

Every point on the planet receives around 4380 hours of daylight and the same amount of darkness each year.

Away from the equator, the ratio varies significantly from month to month, and outside of the tropical latitudes the variation is so large that the year is divided into summer (when there is more than 12 hours of daylight in every 24, and the mean daytime temperature is significantly higher than the annual mean) and winter (when the opposite occurs). 

At the poles, the sun is continuously above the horizon for 6 months (summer) and below the horizon for the other 6 months (winter). 

Visitors from other planets may find this fascinating. Most earthdwellers just build their lives around it.
Title: Re: The amount of daylight in summer and winter?..
Post by: Bored chemist on 21/10/2020 08:47:29
- 4th January is when the Earth is closest to the Sun (perihelion), which makes the sunlight slightly more intense, but does not affect the hours of sunlight very much.
So that's when the earth receives most sunlight.
Also, if your bit of the world gets  Summer and Winter then early January is one of them. - depending where you are.
So Summer or Winter is when the Earth gets the largest amount of sunshine.
So, looking at the OP's question
Why is there the same amount of daylight in summer as there is in winter?
We see that in Summer or Winter (depending on which hemisphere you are in) the amount of Sunshine is either  a maximum or a minimum.
So there isn't the same amount of sunshine in Summer or in Winter.
So the reply to the OP should be


There isn't.


Sorry for not spelling that out earlier; I thought it was obvious.
Title: Re: The amount of daylight in summer and winter?..
Post by: NakedTruth on 11/11/2020 09:41:19
And then there is the north, where you either have sun or darkness for a long time period. Must be crazy to not see the sunlight for so many months..