Native Time Zone field type (with ISO/IANA standards support)

[alexanderloewe]

Summary

Craft CMS would benefit from a dedicated Time Zone field type — a first-class field that lets editors pick a time zone from a pre-populated list of all IANA time zones, similar to how a Country field provides a complete list of ISO 3166 countries.

Motivation

Craft already works with time zones extensively under the hood:

• The system time zone is configured under Settings → General.
• The Date field has a "Show Time Zone" option, which surfaces a time zone picker next to the date/time input.
• Internally, Craft uses PHP's DateTimeZone, which is backed by the IANA tz database (~600 zone identifiers like Europe/Berlin, America/Los_Angeles, Asia/Tokyo).

So the data set already exists in the platform and is actively used. What's missing is the ability to store a time zone as a standalone value on an entry, without it being coupled to a specific date/time.

Use cases

• Storing the time zone of an event venue, office, or user — independent of any specific event date.
• Storing a "default time zone" on a user profile, location entry, or site/channel section.
• Multi-region content where editors need to tag content with a target time zone for scheduling, display, or API consumers.
• Decoupling "when something happens" (Date field) from "what time zone the entity lives in" (Time Zone field).

Right now, achieving this requires either:

1. A Dropdown field where the developer manually maintains a list of ~600 IANA identifiers, or
2. A third-party plugin, or
3. Misusing the Date field's time-zone toggle just to capture the zone.

None of these are ideal given that Craft already ships with the full data set via PHP.

Proposed feature

A new Time Zone field type with:

• A searchable dropdown pre-populated from DateTimeZone::listIdentifiers() (full IANA tz database).
• Field settings to:
  • Group zones by region (Africa, America, Antarctica, Arctic, Asia, Atlantic, Australia, Europe, Indian, Pacific, plus UTC and Etc/*).
  • Optionally restrict to a curated subset (e.g. only Europe/*).
  • Choose the display format (see below).
  • Set a default value (e.g. system time zone, or a fixed zone).
• A normalized return value as a PHP DateTimeZone object in Twig/PHP, with the raw IANA identifier accessible as a string.
• GraphQL support that returns the identifier as a string.

Relevant standards

For the format/display options, the following standards are relevant:

• IANA Time Zone Database (tzdb / "Olson database") — the canonical, region-based identifiers such as Europe/Berlin. Maintained by IANA under [BCP 175 / RFC 6557](https://www.rfc-editor.org/info/bcp175). This is what PHP and Craft already use internally. Not technically an ISO standard, but the de-facto global standard for time zone identification.
• ISO 8601 — defines date and time representations, including UTC offsets such as +01:00, -08:00, or Z for UTC. A Time Zone field could optionally expose the current offset in this format.
• RFC 3339 — an ISO 8601 profile for use in Internet protocols (e.g. 2026-05-12T14:30:00+02:00).
• RFC 9557 — extends RFC 3339 to allow embedding a tzdb identifier as a suffix, e.g. 2026-05-12T14:30:00+02:00[Europe/Berlin]. Useful for systems that want to preserve the named zone alongside the offset.
• ISO 3166-1 — country codes; already referenced by the tz database's zone.tab / zone1970.tab to associate zones with countries. Could be used to power the "group by country" display option.

Suggested display formats in the field settings:

• IANA identifier: Europe/Berlin
• Localized name: "Central European Time (Berlin)"
• ISO 8601 offset: UTC+01:00 (with a note that this changes with DST)
• RFC 9557 style for export: [Europe/Berlin]