System and User Timezones in ServiceNow

There is sometimes confusion on how the system default timezone interacts with a user's custom timezone and how it can be set on an instance.

It is also helpful to understand the hierarchy of the user's and the default timezone on an instance.

Overview

The default timezone for an instance is usually set during the initial configuration of the instance.  This value is set using the glide.sys.default.tz property in the instance. In a new instance, this value is usually blank, so before an instance is released for public use this value should be set with a valid timezone value. The value set in this system property will be the value that is used to determine the display value for date/time values for most record types in the system.  The setting for this value will not modify the actual value stored in the underlying field on the instance but is simply used to modify the value for display purposes in a record.  The value is stored in the field itself in UTC format (Coordinated Universal Time).

If for any reason, a default timezone is not set, the system will default to the time zone setting used by the Java Virtual Machine (JVM) on the server.

If a user has a personalized time zone set in his user preferences (which is stored in that individual's user record on the instance), that value will override the setting found in the instance's system property setting which is used for the determination of the conversion to the date/time value which is displayed for that particular user for date/time values within records.

Changing the default system timezone value

Occasionally, it may be necessary to change this default system timezone setting on the instance. Although this will not change the actual date/time values that are stored in any records on the instance, it could cause confusion for users who don't have their own timezone preference set. For these users, the data/time values that are displayed in records will suddenly show in a different timezone than before. Before making this change, particularly on a production instance, it is recommended to provide a global announcement to all users of the system that this will take place.

Users who have a timezone preference already selected will not notice any difference in the values.

To change this value, follow these steps:

1. Log in to the instance using an admin account.
2. Navigate to: System Properties > Basic Configuration.
3. Scroll to the System timezone for all users unless overridden in the user's record heading
4. From the pull-down menu, select the appropriate timezone value you would like to set as the default for the instance (i.e. US/Pacific).
   
   • If you notice that the current value is "System", this indicates that the time zone is the default time zone from the server.
5. Save.