Index: mod/assignment/lib.php
===================================================================
--- mod/assignment/lib.php	(revision 17556)
+++ mod/assignment/lib.php	(working copy)
@@ -1861,7 +1861,7 @@
                 $info->username = fullname($user, true);
                 $info->assignment = format_string($this->assignment->name,true);
                 $info->url = $CFG->wwwroot.'/mod/assignment/submissions.php?id='.$this->cm->id;
-                $info->timeupdated = strftime('%c',$submission->timemodified);
+                $info->timeupdated = userdate($submission->timemodified, '%c', $teacher->timezone);
 
                 $postsubject = $strsubmitted.': '.$info->username.' -> '.$this->assignment->name;
                 $posttext = $this->email_teachers_text($info);