Change throughout the day

I have a sign that I want to change to a certain texture at different times of the day. Instead of just the normal day/night like in auto-lights, I need morning/afternoon/night.

I'm not sure how I do that, though I assume it has something to do with the sun's position. Could anyone give me a hint or point me in the right direction please?

Just sample the sun direction more often, and set up arbitrary check.

if(angle >= lowmidday && angle <= highmidday)
{
it's mid day
}

or something like that.. where low and high midday are the minimum and maximum angle you want for the sun... something like that

Alright, still a bit lost, think I haven't slept enough, but how would I add such an adaption into a script like below:

  default 
 {
    state_entry() 
    {
       llSetTimerEvent(60);
    }
    timer() 
    {
       vector sun = llGetSunDirection();
          if(sun.z > 0) 
         {
             llSetTexture("day_texture",ALL_SIDES);
         }
          else 
         {
             llSetTexture("night_texture",ALL_SIDES);
         }
    }
 }
 

Also, is that timer okay, or can it be set higher?

Well, I suppose you could do something like this, though be advised that they have modified the sun's path through the sky in a very strange way (it "orbits" a point to the South someplace ABOVE the ground in order to make the day longer than the night):

vector sunDir = llGetSunDirection();
float sunAngle = llAtan2(sunDir.z, sunDir.x);
if (sunAngle < 0.0)
{
   sunAngle += TWO_PI;
}

if (sunAngle < 0.4*PI)
{
   // Morning
} else if (sunAngle < 0.6*PI)
{
   // Midday
} else if (sunAngle < 0.8*PI)
{
   // Afternoon
} else if (sunAngle < PI)
{
   // Evening
} else
{
   // Night
}

Based on that, would this work?

     default 
      {
         state_entry() 
         {
            llSetTimerEvent(60);
         }
         timer() 
         {
            vector sunDir = llGetSunDirection();
    float sunAngle = llAtan2(sunDir.z, sunDir.x);
    if (sunAngle < 0.0)
    {
       sunAngle += TWO_PI;
    }
    
    if (sunAngle < 0.4*PI)
    {
  llSetTexture("morning_texture",ALL_SIDES);       
 } else if (sunAngle < 0.8*PI)
    {
  llSetTexture("afternoon_texture",ALL_SIDES);
 }  else
    {
       llSetTexture("night_texture",ALL_SIDES);
    }
    
         }
      }

Sure. I'd think so. You might want some logic in there to see if the texture has changed from the last time. Not sure if setting a texture redundantly has any affect on clients and object update messages and such.