How to add day/night cycle in specific locations

I want to add day/night cycle in specific location.
For example : It will be day until character reach the cave,when he leave the cave from other side it will be night.
Anyone knows how to make this happen?

Level Streaming can be used for this. Simply make a level for the Day part. One Level for the Cave. And one Level for the night part and connect them via Level Streaming.

So basically finish first level as day,player enters the cave,create level with night time,and trigger it with trigger c. (Trigger will be putted near exit of the cave) right?