diff -Naur WebCalendar-1.2.0.orig/includes/functions.php WebCalendar-1.2.0.new/includes/functions.php
--- WebCalendar-1.2.0.orig/includes/functions.php	2009-10-12 15:32:31.000000000 +0200
+++ WebCalendar-1.2.0.new/includes/functions.php	2009-10-12 15:50:35.000000000 +0200
@@ -139,6 +139,29 @@
   return sprintf ( "%d%02d00", $minutes / 60, $minutes % 60 );
 }
 
+/* Bump UNIX local timestamp with the given duration.
+ * param int $ts		input timestamp
+ * param int $hour		hour duration
+ * param int $minute		minute duration
+ * param int $second		second duration
+ * param int $month		month duration
+ * param int $day		day duration
+ * param int $year		year duration
+ *
+ * This function overcomes problems due to daylight saving change dates;
+ *   it is based on the fact that function mktime() accepts out of range
+ *   data.
+ */
+
+function bump_local_timestamp($ts, $hour = 0, $minute = 0, $second = 0,
+	$month = 0, $day = 0, $year = 0)
+
+{
+	return mktime(date('G', $ts) + $hour, date('i', $ts) + $minute,
+		date('s', $ts) + $second, date('n', $ts) + $month,
+		date('j', $ts) + $day, date('Y', $ts) + $year);
+}
+
 /* Builds the HTML for the event label.
  *
  * @param string  $can_access
diff -Naur WebCalendar-1.2.0.orig/includes/init.php WebCalendar-1.2.0.new/includes/init.php
--- WebCalendar-1.2.0.orig/includes/init.php	2009-10-12 15:32:31.000000000 +0200
+++ WebCalendar-1.2.0.new/includes/init.php	2009-10-12 15:55:43.000000000 +0200
@@ -411,8 +411,8 @@
     $wkstart = get_weekday_before ( $y, $m, $d );
     $lastDay = ( $DISPLAY_WEEKENDS == 'N' ? 4 : 6 );
     for ( $i = -5; $i <= 9; $i++ ) {
-      $twkstart = $wkstart + ( 604800 * $i );
-      $twkend = $twkstart + ( 86400 * $lastDay );
+      $twkstart = bump_local_timestamp($wkstart, 0, 0, 0, 0, 7 * $i, 0);
+      $twkend =  bump_local_timestamp($twkstart, 0, 0, 0, 0, $lastDay, 0);
       $dateSYmd = date ( 'Ymd', $twkstart );
       $dateEYmd = date ( 'Ymd', $twkend );
       $dateW = date ( 'W',  $twkstart + 86400 );
diff -Naur WebCalendar-1.2.0.orig/view_v.php WebCalendar-1.2.0.new/view_v.php
--- WebCalendar-1.2.0.orig/view_v.php	2008-03-07 21:15:45.000000000 +0100
+++ WebCalendar-1.2.0.new/view_v.php	2009-10-12 16:04:55.000000000 +0200
@@ -34,10 +34,10 @@
 $nextdate = date ( 'Ymd', mktime ( 0, 0, 0, $thismonth, $thisday + 7, $thisyear ) );
 $prevdate = date ( 'Ymd', mktime ( 0, 0, 0, $thismonth, $thisday - 7, $thisyear ) );
 
-$wkstart = get_weekday_before ( $thisyear, $thismonth, $thisday + 1 );
-
-$wkend = $wkstart + ( 86400 * ( $DISPLAY_WEEKENDS == 'N' ? 5 : 7 ) );
-$thisdate = date ( 'Ymd', $wkstart );
+$wkstart = get_weekday_before($thisyear, $thismonth, $thisday + 1);
+$wkend = bump_local_timestamp($wkstart, 0, 0, 0, 0,
+	$DISPLAY_WEEKENDS == 'N'? 5: 7, 0) - 1;
+$thisdate = date('Ymd', $wkstart);
 
 $nextStr = translate ( 'Next' );
 $prevStr = translate ( 'Previous' );
@@ -108,7 +108,8 @@
     $body .= '
       <tr>
         <th class="row" style="width:' . $tdw . '%;">' . $tempfullname . '</th>';
-    for ( $date = $wkstart; $date < $wkend; $date += 86400 ) {
+    for ($date = $wkstart; $date <= $wkend;
+     $date = bump_local_timestamp($date, 0, 0, 0, 0, 1, 0)) {
       $is_weekend = is_weekend ( $date );
       if ( $is_weekend && $DISPLAY_WEEKENDS == 'N' )
         continue;