Thank you for your advice.
<?php include( get_template_directory() . '/data.php' ); include( get_template_directory() . '/icon.php' ); ?>
The script above works but when I put it in Theme Editor in header.php
It is not executed after inserting into ‘Ad location’ window – “Top Header”.
So, my question is now where should I paste the script to have the text just below the weather banner?