diff --git a/upload/ajax.php b/upload/ajax.php
index b2f5da778..ec5d46bd9 100644
--- a/upload/ajax.php
+++ b/upload/ajax.php
@@ -82,7 +82,9 @@ class ajax_common
 		'posts'             => array('guest'),
 		'birthday_list'     => array('guest'),
 		'get_forum_mods'    => array('guest'),
-	);
+
+		'change_tz'         => array('user'),
+);
 
 	var $action = null;
 
@@ -498,5 +500,19 @@ class ajax_common
 	{
 		require(AJAX_DIR .'topic_tpl.php');
 	}
-}
 
+	function change_tz()
+	{
+		global $bb_cfg, $userdata;
+		$tz = (int) $this->request['tz'];
+		if ($tz < -12) $tz = -12;
+		if ($tz > 13) $tz = 13;
+		if ($tz != $bb_cfg['board_timezone'])
+		{
+			// Set current user timezone
+			DB()->query("UPDATE ". BB_USERS ." SET user_timezone = $tz WHERE user_id = ". $userdata['user_id'] ." LIMIT 1");
+			$bb_cfg['board_timezone'] = $tz;
+			cache_rm_user_sessions ($userdata['user_id']);
+		}
+	}
+}
diff --git a/upload/templates/default/page_header.tpl b/upload/templates/default/page_header.tpl
index 470bc6071..09b949529 100644
--- a/upload/templates/default/page_header.tpl
+++ b/upload/templates/default/page_header.tpl
@@ -328,6 +328,26 @@ function OpenInEditor ($file, $line)
 <!--/logo-->
 
 <!-- IF LOGGED_IN -->
+
+<script type="text/javascript">
+ajax.change_tz = function(tz) {
+	ajax.exec({
+		action     : 'change_tz',
+		tz      : tz,
+	});
+};
+ajax.callback.change_tz = function(data) {
+};
+$(document).ready(function() {
+	x = new Date();
+	tz = -x.getTimezoneOffset()/60;
+	if (tz != <?php echo $bb_cfg['board_timezone']?>)
+	{
+		ajax.change_tz(tz);
+	}
+});
+</script>
+
 <!--logout-->
 <div class="topmenu">
 <table width="100%" cellpadding="0" cellspacing="0">
diff --git a/upload/templates/default/usercp_register.tpl b/upload/templates/default/usercp_register.tpl
index 6f3e6bd80..2cec45127 100644
--- a/upload/templates/default/usercp_register.tpl
+++ b/upload/templates/default/usercp_register.tpl
@@ -15,6 +15,15 @@ ajax.callback.user_register = function(data){
 <!-- IF ADM_EDIT -->
 <input type="hidden" name="u" value="{PR_USER_ID}" />
 <!-- ENDIF -->
+<!-- IF not ADM_EDIT -->
+<script type="text/javascript">
+x = new Date();
+tz = -x.getTimezoneOffset()/60;
+document.write('<input type="hidden" name="user_timezone" value="'+tz+'" />');
+</script>
+<!-- ELSE -->
+<input type="hidden" name="user_timezone" value="{USER_TIMEZONE}" />
+<!-- ENDIF -->
 
 <table class="forumline usercp_register">
 <col class="row1" width="35%">
@@ -130,10 +139,6 @@ ajax.callback.gen_passkey = function(data){
 	<td>{LANGUAGE_SELECT}</td>
 </tr>
 <!-- ENDIF -->
-<tr>
-	<td>{L_TIMEZONE}:</td>
-	<td>{TIMEZONE_SELECT}</td>
-</tr>
 <!-- IF EDIT_PROFILE -->
 <tr>
 	<th colspan="2">{L_PREFERENCES}</th>