Greet user based on time

GreetUser.php

<?php
  date_default_timezone_set('Asia/Kolkata');
  $hour=date('h', time());
  $ampm=date('a', time());

  if($ampm=="am"){
      if($hour>=1 && $hour<=11){
          echo "Good Morning!!!";
      }
  }
  else if($ampm=="pm"){
      if(($hour>=1 && $hour<=4) || $hour==12){
          echo "Good Afternoon!!!";
      }
      else if($hour>=4 && $hour<=9){
          echo "Good Evening!!!";
      }
      else{
          echo "Good Night!!!";
      }
  }
  ?>