title: CenOS shows incorrect week number
body: <p>I'm using php date('W'); function to get a number of the week of this year.</p>
  
  <pre><code>date('W')  says "40" (that's correct).
  </code></pre>
  
  <p>The problem is, that my Linux machine, CentOS has a correct date, but shows incorrect week number.</p>
  
  <pre><code>date +"%W" says "39"
  </code></pre>
  
  <p>Does anyone know why it works this way and how could I fix it?</p>