Find out if current system time and time zone services status: timedatectl status.
If your "Time zone" is correct (Hongkong, in my case), and the "NTP enabled" is "no", then you should open time synchronization service.
Run the following commands as root to set correct timezne and sync time with Internet.
# ln -s /usr/share/zoneinfo/Hongkong /etc/localtime
# hwclock --systohc --utc
# systemctl enable systemd-timesyncd.service
# systemctl start systemd-timesyncd.service
Ref: Time - ArchWiki