If you're dual-booting Ubuntu 18.04 and Windows 10, you may find that changing time in one system affects the other and the two systems can't display the same time.
This happens as Ubuntu interprets the hardware clock or real time clock (RTC) in universal time (UTC) by default while Windows 10 maintains the clock in local time.
You can fix this by keeping RTC in local time in Ubuntu by running a command in the terminal below.
timedatectl set-local-rtc 1 --adjust-system-clock
To undo this setting, enter the command below.
timedatectl set-local-rtc 0 --adjust-system-clock