Index: wp-settings.php
===================================================================
--- wp-settings.php	(revision 6124)
+++ wp-settings.php	(working copy)
@@ -261,6 +261,10 @@
 
 do_action('sanitize_comment_cookies');
 
+if ( version_compare( '5.1', phpversion(), '<=' ) && empty( ini_get('date.timezone') ) && FALSE === getenv('TZ') ) {
+	date_timezone_set('UTC');	
+}
+
 $wp_the_query =& new WP_Query();
 $wp_query     =& $wp_the_query;
 $wp_rewrite   =& new WP_Rewrite();