diff --git a/src/core.c/Rakudo/Internals.pm6 b/src/core.c/Rakudo/Internals.pm6
index c326c56f2ab..45ba646b1a2 100644
--- a/src/core.c/Rakudo/Internals.pm6
+++ b/src/core.c/Rakudo/Internals.pm6
@@ -768,7 +768,7 @@ implementation detail and has no serviceable parts inside"
     }
 
 # Keep track of the differences between TAI and UTC for internal use.
-# The "BEGIN" and "END" comments are for tools/update-tai-utc.pl.
+# The "BEGIN" and "END" comments are for tools/add-leap-second.raku.
 #
 # Some handy tables:
 # http://tf.nist.gov/pubs/bulletin/leapsecond.htm
diff --git a/tools/add-leap-second.raku b/tools/add-leap-second.raku
new file mode 100755
index 00000000000..9fbd147e032
--- /dev/null
+++ b/tools/add-leap-second.raku
@@ -0,0 +1,34 @@
+#!raku
+
+# This helper script is intended to make adding leap seconds to the
+# Raku system as easy as possible: by just giving the date for which
+# to add the leap second, it will scan the file for current leap
+# second information and add leap second information for that date
+# to the source, which is output to STDOUT.  After inspection one
+# can then just overwrite the source-file and a re-compilation
+# of the setting should then be enough to activate the new leap
+# second in Raku's time logic.
+
+use v6.c;
+
+sub MAIN(
+  #| the date for which to add a leap second
+  Str $the-date,
+  #| the source file containing leap second logic (default: src/core.c/Rakudo/Internals.pm6)
+  $from = 'src/core.c/Rakudo/Internals.pm6'
+) {
+
+    # set up the new leap second info
+    my $date   = Date.new($the-date);
+    my $epoch  = $date.DateTime.posix;
+    my $before = $date.earlier(:1day);
+
+    # run through the source file and update as appropriate
+    for $from.IO.lines -> $line {
+        say "        '$before',"
+          if $line eq '        #END leap-second-dates';
+        say "        $epoch,"
+          if $line eq '        #END leap-second-posix';
+        say $line;
+    }
+}
diff --git a/tools/update-tai-utc.pl b/tools/update-tai-utc.pl
deleted file mode 100755
index 74cdb9927cf..00000000000
--- a/tools/update-tai-utc.pl
+++ /dev/null
@@ -1,47 +0,0 @@
-#!/usr/bin/perl
-# Updates src/core/tai-utc.pm6.
-
-use warnings;
-use strict;
-use Time::y2038 'timegm';
-use File::Slurp qw(slurp write_file);
-use LWP::Simple 'get';
-
-my $url = 'ftp://hpiers.obspm.fr/iers/bul/bulc/TimeSteps.history';
-
-$ARGV[0] ||= 'src/core/Rakudo/Internals.pm6';
-my $tu_path = $ARGV[0];
-
-my @dates = do {
-    my @lines = split /\n/, get $url;
-    pop @lines;
-    shift @lines until $lines[0] =~ /\A 1972  Jul\.   1/;
-    map {
-        /(\d{4})  (Jan|Jul)/;
-        $2 eq 'Jan' ? [$1 - 1, 12, 31] : [$1, 6, 30]
-    } @lines
-};
-
-my $tu = slurp $tu_path;
-sub replace {
-    my ($find, $fmt, $f) = @_;
-    $tu =~ s
-        {^( *)#BEGIN $find\n.+?^ *#END $find\n}
-        { sprintf "$1#BEGIN $find\n%s\n$1#END $find\n", join "\n",
-              map { sprintf "%s$fmt,", $1, $f->(@$_) } @dates }ems
-      or die "Couldn't replace $find";
-}
-replace 'leap-second-dates', "'%d-%02d-%02d'", sub { @_ };
-replace 'leap-second-posix', '%10d', sub {
-    my ($y, $m, $d) = @_;
-    1 + timegm 59, 59, 23, $d, $m - 1, $y - 1900;
-};
-write_file $tu_path, $tu;
-print "Updated.\n";
-
-# The IERS announces midyear leap seconds in early January and
-# end-of-year leap seconds in early July. So:
-
-my $month = (gmtime)[4];
-printf "This program should next be run in %s.\n",
-    1 < $month && $month < 8 ? 'August' : 'February';