diff --git a/ChangeLog b/ChangeLog
index 47b7bde..d939220 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,8 @@
 btrbk-current
 
+  * Bugfix: fix monthly schedule if older than 10 weeks (close: #59).
   * Bugfix: fix sprintf used by config option "timestamp_format long"
-    when using perl-5.22.0 (close: #57)
+    when using perl-5.22.0 (close: #57).
 
 btrbk-0.21.0
 
diff --git a/btrbk b/btrbk
index 2083b9a..9ad21ca 100755
--- a/btrbk
+++ b/btrbk
@@ -1895,14 +1895,14 @@ sub schedule(@)
     }
     $first_in_delta_weeks{$href->{delta_weeks}} //= $href;
   }
-  foreach (reverse sort keys %first_in_delta_weeks) {
+  foreach (sort {$b <=> $a} keys %first_in_delta_weeks) {
     my $href = $first_in_delta_weeks{$_} || die;
     if($preserve_weekly && (($preserve_weekly eq "all") || ($href->{delta_weeks} <= $preserve_weekly))) {
       $href->{preserve} ||= "preserved weekly: $href->{delta_weeks} weeks ago, " . ($href->{err_days} ? "+$href->{err_days} days after " : "on ") . "$preserve_day_of_week";
     }
     $last_weekly_in_delta_months{$href->{delta_months}} = $href;
   }
-  foreach (reverse sort keys %last_weekly_in_delta_months) {
+  foreach (sort {$b <=> $a} keys %last_weekly_in_delta_months) {
     my $href = $last_weekly_in_delta_months{$_} || die;
     if($preserve_monthly && (($preserve_monthly eq "all") || ($href->{delta_months} <= $preserve_monthly))) {
       $href->{preserve} ||= "preserved monthly: " . ($href->{err_days} ? "$href->{err_days} days after " : "") . "last $preserve_day_of_week of month $href->{month} (age: $href->{delta_months} months)";