You should consider setting up ntp on your servers to manage time. ntp polls external time sources and keeps your machine synced up. It also slowly slews the clock over time to keep it in sync, instead of making large time changes all at once. This produces less surprises and helps keep applications from getting confused.
Typically you set up one machine in your organization to run ntp and that machine communicates with an external ntp server. Then, your other servers contact your designated ntp master for their updates. You can use this ntp server tool to find an appropriate external server for you to use. Generally you want to connect to external servers which are geographically close to you.