Array index is out of range??? (Day Night Cycle Script)

Hi unity community

I got this error and i dont know what it means:
IndexOutOfRangeException: Array index is out of range.
DayNightCycle.ChangeTime () (at Assets/Models + Scripts/Scripts/CSharp/DayNightCycle.cs:38)
DayNightCycle.Update () (at Assets/Models + Scripts/Scripts/CSharp/DayNightCycle.cs:25)

This is my code:

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

public class DayNightCycle : MonoBehaviour 
{
	public float time;
	public TimeSpan currenttime;
	public Transform SunTransform;
	public Light Sun;
	public Text timetext;
	public int days;

	public float intensity;
	public Color fogday = Color.grey;
	public Color fognight = Color.black;

	public int speed;

	// Update is called once per frame
	void Update () 
	{
		ChangeTime ();	
	}

	public void ChangeTime()
	{
		time += Time.deltaTime * speed;
		if (time > 86400) 
		{
			days += 1;	
			time = 0;
		}
		currenttime = TimeSpan.FromSeconds (time);
		string[] temptime = currenttime.ToString ().Split ("+"[0]);
		timetext.text = temptime [0] + ":" + temptime [1];

		SunTransform.rotation = Quaternion.Euler (new Vector3 ((time - 21600) / 86400 * 360, 0, 0));
		if(time < 43200)
			intensity = 1 - (43200 - time) / 43200;
		else
			intensity = 1 - ((43200 - time) / 43200 *-1);

		RenderSettings.fogColor = Color.Lerp (fognight, fogday, intensity * intensity);

		Sun.intensity = intensity;
	}
}

can someone help me?

Check out 35-39 lines. It has something to do with the array.

The error you get means that you are trying to access (use) or assign a new value to the string array number, which does not exist or has not been created yet.