After putting a fresh installation of Linux Mint 18.3 (Sylvia) in place on my dual-booted laptop computer, I noticed that the system date was fours hours slow. Previously, I found this to be related to the difference in which Windows and Linux handle time. In particular, Windows uses local time while Linux uses Universal Time Coordinated (UTC). However, the previous fix no longer worked.
Earlier, I came across this issue due to a problem synchronizing my data files while using FreeFileSync in both Windows and Linux (See: Installing FreeFileSync in Linux Mint 18). The previous fix was to run the Terminal command: sudo timedatectl set-local-rtc 1; however, this now had no effect on the time displayed on the system clock.
Fortunately, a slightly different form of this command has been documented by Chris Hoffman, writing for How-To Geek. The following command now tells Linux to use local time:
sudo timedatectl set-local-rtc 1 --adjust-system-clock
Installing FreeFileSync in Linux Mint 18
How to Fix Windows and Linux Showing Different Times When Dual Booting