Directional Light makes scene too dark when positioned straight up

So i made a day/night cycle script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class TimeScript : MonoBehaviour {
	private void Update() 
	{
		transform.Rotate (Vector3.right, 1.0f);
	}
}

Very simple, the directional light rotates.
But when it points straight up, the scene becomes completely dark and it shouldn’t

Screenshots: Day: Imgur: The magic of the Internet

Night: Imgur: The magic of the Internet

Help

My painfully complicated method might help out with this problem. Have a second directional light in the same spot, pointed nearly directly up (about -89.9 on the x-axis). Attach a script that will enable the 2nd light when the 1st light’s rotation is directly up (-90 on the x-axis). Then have the script disable it when the 1st light’s rotation starts to come down.