New answers tagged connotation
There is really not much of a difference, I think. Perhaps den ganzen Tag über could be translated as all day long.
It's one of the basic functions of über, meaning lang or während. For me there's no difference in meaning. Maybe the variant without über is even a contraction of the one with it. Additionally, here's a drawing: Fits, doesn't it? Apart from this intuitive approach, I can't find any other (e.g. etymological) "reasons" for über in this context.
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