Made a change to /etc/sysconfig/ntpdate:
# Options for ntpdate
OPTIONS="-u -p 2"
# Number of retries before giving up
RETRIES=2
# Set to 'yes' to sync hw clock after successful ntpdate
SYNC_HWCLOCK=yes
Then, enable the service and start it:
$ sudo systemctl enable ntpdate.service
$ sudo systemctl start ntpdate.service
An annoyance: systemctl and sysctl are way too similar and do completely different things.