diff --git a/calendar/lib.php b/calendar/lib.php
index c1455c681c5..93c04f3a491 100644
--- a/calendar/lib.php
+++ b/calendar/lib.php
@@ -62,6 +62,8 @@ define ('CALENDAR_URL', $CFG->wwwroot.'/calendar/');
 define ('CALENDAR_TF_24', '%H:%M');
 define ('CALENDAR_TF_12', '%I:%M %p');
 
+$CALENDARDAYS = array('sunday','monday','tuesday','wednesday','thursday','friday','saturday');
+
 // Initialize the session variables here to be sure
 calendar_session_vars();
 
@@ -536,7 +538,7 @@ function calendar_sql_where($tstart, $tend, $users, $groups, $courses, $withdura
 }
 
 function calendar_top_controls($type, $data) {
-    global $CFG;
+    global $CFG, $CALENDARDAYS;
     $content = '';
     if(!isset($data['d'])) {
         $data['d'] = 1;
@@ -595,11 +597,10 @@ function calendar_top_controls($type, $data) {
         break;
         case 'day':
             $data['d'] = $date['mday']; // Just for convenience
-            $dayname = calendar_wday_name($date['weekday']);
             $prevdate = usergetdate(make_timestamp($data['y'], $data['m'], $data['d'] - 1));
             $nextdate = usergetdate(make_timestamp($data['y'], $data['m'], $data['d'] + 1));
-            $prevname = $prevdate['weekday'];
-            $nextname = $nextdate['weekday'];
+            $prevname = calendar_wday_name($CALENDARDAYS[$prevdate['wday']]);
+            $nextname = calendar_wday_name($CALENDARDAYS[$nextdate['wday']]);
             $content .= '<table class="calendar-controls"><tr>';
             $content .= '<td class="previous"><a href="'.calendar_get_link_href('view.php?view=day&amp;', $prevdate['mday'], $prevdate['mon'], $prevdate['year']).'">&lt;&lt; '.$prevname."</a></td>\n";
 
diff --git a/calendar/view.php b/calendar/view.php
index 9841084281c..8281b07adf5 100644
--- a/calendar/view.php
+++ b/calendar/view.php
@@ -261,7 +261,7 @@ function calendar_show_day($d, $m, $y, $courses, $groups, $users) {
 }
 
 function calendar_show_month_detailed($m, $y, $courses, $groups, $users) {
-    global $CFG, $SESSION, $USER;
+    global $CFG, $SESSION, $USER, $CALENDARDAYS;
     global $day, $mon, $yr;
 
     $getvars = 'from=month&amp;cal_d='.$day.'&amp;cal_m='.$mon.'&amp;cal_y='.$yr; // For filtering
@@ -343,11 +343,10 @@ function calendar_show_month_detailed($m, $y, $courses, $groups, $users) {
     echo '<table class="calendarmonth"><tr class="weekdays">'; // Begin table. First row: day names
 
     // Print out the names of the weekdays
-    $days = array('sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday');
     for($i = $display->minwday; $i <= $display->maxwday; ++$i) {
         // This uses the % operator to get the correct weekday no matter what shift we have
         // applied to the $display->minwday : $display->maxwday range from the default 0 : 6
-        echo '<th>'.get_string($days[$i % 7], 'calendar').'</th>';
+        echo '<th>'.get_string($CALENDARDAYS[$i % 7], 'calendar').'</th>';
     }
 
     echo '</tr><tr>'; // End of day names; prepare for day numbers