The time zone database

The Time Zone Database (tzdata) provides Red Hat Enterprise Linux (RHEL) with data that is specific to the local time zone. Applications in the Linux operating system use this data for various purposes. For instance, the GNU C Library (glibc) uses tzdata to ensure APIs such as strftime() work correctly, while applications such as /usr/bin/date use it to print the local date.

The tzdata package contains data files documenting both current and historic transitions for various time zones around the world. This data represents changes required by local government bodies or by time zone boundary changes, as well as changes to coordinated universal time (UTC) offsets and daylight saving time (DST).

This article is a quick update about changes to the tzdata package in 2019, as well as possible time zone changes that we are monitoring for package updates in 2020.

Note: Occasionally, tzdata changes are announced without much lead time, or with incomplete information. In these cases, we try to plan for different scenarios and rely on upstream maintainers to make decisions based on their experience. Once an update is ready, we update our sources, and our quality assurance and release engineers help push the update out as quickly as possible.

Changes to the tzdata package in 2019 and 2020

We released three updates to the tzdata package in 2019, with most changes related to DST start- and end-date transitions. Fiji, Norfolk Island, Palestine, and the Metlakatla Indian Community of Ketchikan, Alaska, all changed their DST start and end dates. Additionally, Brazil no longer observes DST.

To maintain the accuracy of the information provided by the Time Zone Database, the upstream project frequently updates past timestamps as new information becomes available. In 2019, we made corrections to timestamps going back as far as 1866.

In 2020, we will be watching for changes associated with the United Kingdom’s departure from the European Union.

The upstream time zone project releases updates on, where you can also find information about subscribing to the tzdata email list and accessing the archives. The email list includes discussions of proposed changes and corrections, release announcements, and time zone-related news references.

For information specific to Red Hat Enterprise Linux, see the Red Hat Enterprise Linux Timezone Data (tzdata) Development Status Page.

Last updated: June 29, 2020