Preposition

In the northern hemisphere, it’s getting hotter every day throughout July.
(or) It’s getting hotter every day throughout July in the northern hemisphere.

Are all of the other prepositions, (A)~(C), wrong?

On closer examination of the sentence, it would have to be a prediction rather than after the fact statement, in which case, “It will get hotter every day in July, every day during July, and every day throughout July.” will work for me. (“over” seems not to fit.)
For a continuous thought, “It is getting hotter every day” is a comment based on days that have passed; and to make it include the

Then, how about the present tense? For example, "It gets hotter every day [ (A) in / (B) over / (C) during / (D) throughout / (E) of ] July", which one is right among (A)~(E)?

Yes, there is room to consider the situation as a ‘generalization’. As a comment on the weather in general, you might say, “It gets hotter every day ‘in July’.” It is (of course) not the same as, “The bath water gets hotter every minute, with the hot tap turned on.” (That would be factual.)

“It gets hotter every day ‘over’ and ‘during’ July” are both exaggerations of the truth, but migh

I see. Then, how about "It gets hotter every day of July"?

Yes, that sounds OK. While the sentence is OK, there is no guarantee that the right interpretation will be made, since it isn't a common prediction.