Yay done 
I didnt use the Day/Night Cycle you used but that doesnt matter in the end. I didnt like the one you used because i couldnt get rid of the “Bright Night”, maybe i just didnt copy the BP corectly from the YouTube Video. However here is a example of how to turn a light on at night and turn it of at day.
Stuff i used:
- Gregdumb’s time-of-day skydome blueprint
- Grass/Bush and Tree Asset from: (MetalGameStudios) (Unreal Engine 4: free grass (download link) - YouTube)
thx to those ppl for creating this stuff
IMPORTANT! Un7Zip the DemoProject Folder to your UE4 Projects Folder AND copy over a StarterContent Texture Folder into DemoProject\Content
I removed those for the sake of filesize (like 60mb)-
Howerver here is the link: (88mb)
If you got questions just ask here 