Control the sun, fog, ambient light, and sun rotation through curves and gradients.

TimeOfDayManager

using UnityEngine;

public class TimeOfDayManager : MonoBehaviour
{
	public float secondsInFullDay = 120f;

	[HideInInspector]
	public float timeMultiplier = 1f;



	[Range(0.0f, 1f)]
	public float currentTimeOfDay;

	private float sunInitialIntensity;





	#region Curves and Gradients

	[Header("Ambience")]
	public float CurrentAmbientIntensity;
	public Color CurrentAmbientColor;
	public AnimationCurve AmbientCurve;
	public Gradient AmbientColorCurve;

	[Header("Fog")]
	public float FogIntensity;
	public float FogDistance;
	
	public Color CurrentFogColor;
	public Gradient FogColorGradient;

	public AnimationCurve FogColorCurve;
	public AnimationCurve FogIntensityCurve;
	public AnimationCurve FogDistanceCurve; 

	[Header("Sun")]
	public Light sun;
	public AnimationCurve SunLightIntensityCurve;
	public Gradient SunLightColorGradient;


	#endregion

	private void Start()
	{
		this.sunInitialIntensity = this.sun.intensity;
	}

	private void Update()
	{
		this.UpdateSun();
		this.UpdateRenderSettings();
		this.currentTimeOfDay += Time.deltaTime / this.secondsInFullDay * this.timeMultiplier;
		if ((double)this.currentTimeOfDay >= 1.0)
			this.currentTimeOfDay = 0.0f;
		if ((double)this.currentTimeOfDay <= 0.0)
			this.currentTimeOfDay = 0.0f;
		if (Input.GetKey(KeyCode.T))
			this.currentTimeOfDay -= 0.05f;
		if (!Input.GetKey(KeyCode.Y))
			return;
		this.currentTimeOfDay += 0.05f;
	}

	private void UpdateSun()
	{
		this.sun.transform.localRotation = Quaternion.Euler((float)((double)this.currentTimeOfDay * 360.0 - 90.0), 170f, 0.0f);
	}

	private void UpdateRenderSettings()
	{
		this.sun.intensity = this.SunLightIntensityCurve.Evaluate(this.currentTimeOfDay);
		this.sun.color = this.SunLightColorGradient.Evaluate(this.currentTimeOfDay);
		RenderSettings.ambientIntensity = this.AmbientCurve.Evaluate(this.currentTimeOfDay);
		RenderSettings.fogColor = this.FogColorGradient.Evaluate(this.currentTimeOfDay);
		RenderSettings.fogDensity = this.FogIntensityCurve.Evaluate(this.currentTimeOfDay);
		RenderSettings.fogEndDistance = this.FogDistanceCurve.Evaluate(this.currentTimeOfDay);
		RenderSettings.ambientSkyColor = this.AmbientColorCurve.Evaluate(this.currentTimeOfDay);
		this.CurrentAmbientColor = RenderSettings.ambientSkyColor;
		this.CurrentFogColor = RenderSettings.fogColor;
		this.CurrentAmbientIntensity = RenderSettings.ambientIntensity;
	}
}