When Kovu and Simba left Priderock it was sunrise. When Kovu was exiled from the Pridelands it was sunset.Then when Kiara left Priderock to find him it was nighttime so how did it get dark so quickly if these events only lasted for a few minutes.

I understand what you mean, but you also have to think how long it would have took Kovu to get from where Zira scratched him, to get back to Pride rock, I think they only made it that way so that events could be quickened.

wel,it took a while as simba talked to kovu about scar and theen it took a while to kovu to run back to priderock,they just dint show it to make the film shorter

Because in the story, it didn't actually take a couple minutes. Simba's talk with Kovu probably was supposed to be thirty minutos and the ambush scene was supposed to be four hours. Maybe Kovu's exile was supposed to be an hora and Kiara's procurar was two hours.