diff --git a/phpBB/common.php b/phpBB/common.php
index 5f4216d1d7..02b18d6aa1 100644
--- a/phpBB/common.php
+++ b/phpBB/common.php
@@ -21,6 +21,7 @@ $starttime = $starttime[1] + $starttime[0];
 
 // Report all errors, except notices
 error_reporting(E_ALL ^ E_NOTICE);
+date_default_timezone_set('UTC');
 
 /*
 * Remove variables created by register_globals from the global scope
diff --git a/phpBB/style.php b/phpBB/style.php
index 3e923b8f53..2bc6930a5c 100644
--- a/phpBB/style.php
+++ b/phpBB/style.php
@@ -17,6 +17,7 @@ $phpEx = substr(strrchr(__FILE__, '.'), 1);
 
 // Report all errors, except notices
 error_reporting(E_ALL ^ E_NOTICE);
+date_default_timezone_set('UTC');
 
 require($phpbb_root_path . 'config.' . $phpEx);