Dışarıda (hava) güneşliyor.

Its sunny outside.

Thank you

Not quite sure, but I think that güneşlemek means "to sunbathe". As learner, I would try with something similar:

Dışarıda hava güneşli.

Dişarıda - Outside

Hava - Weather

Güneşli(dir) - Is sunny

Btw, I thought that "Dışarıdaki hava güneşii" could be correct too... but google did not find such sentence

There are few ways that you can hear people say  ;

Dışarıda hava güneşli.

Dışarısı güneşli.

Dışarı güneşli.

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note : As Tomac said, "güneşlenmek" is to sunbathe

This is the pearl here:

And I am asking: dışarı of what?

Dışarı of a place in where at the very moment people make this comment.

Say, I am indoors, looking out the window, seeing the sun is shining outside and saying to my friend " Bak, dışarısı güneşli ! " [Look, it is sunny outside], meaning " Look outside of the house is sunny", by dropping the unnecessary item "house" since it is obvious that we both are in the house at the very moment. Using "house" in that case would look bit silly .This is my understanding.

This use of 3rd sg poss fascinates me. I didn´t see it in any other language. You Turks cannot see how extraordinary it is.

Thank you all