zoneinfo — IANA time zone support

Added in version 3.9.

Source code: Lib/zoneinfo

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The zoneinfo module provides a concrete time zone implementation to support the IANA time zone database as originally specified in PEP 615. By default, zoneinfo uses the system’s time zone data if available; if no system time zone data is available, the library will fall back to using the first-party tzdata package available on PyPI.

See also

Module: datetime

Provides the time and datetime types with which the ZoneInfo class is designed to be used.

Package tzdata

First-party package maintained by the CPython core developers to supply time zone data via PyPI.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

Using ZoneInfo

ZoneInfo is a concrete implementation of the datetime.tzinfo abstract base class, and is intended to be attached to tzinfo, either via the constructor, the datetime.replace method or datetime.astimezone:

>>> from zoneinfo import ZoneInfo
>>> import datetime as dt

>>> when = dt.datetime(2020, 10, 31, 12, tzinfo=ZoneInfo("America/Los_Angeles"))
>>> print(when)
2020-10-31 12:00:00-07:00

>>> when.tzname()
'PDT'

Datetimes constructed in this way are compatible with datetime arithmetic and handle daylight saving time transitions with no further intervention:

>>> when_add = when + dt.timedelta(days=1)

>>> print(when_add)
2020-11-01 12:00:00-08:00

>>> when_add.tzname()
'PST'

These time zones also support the fold attribute introduced in PEP 495. During offset transitions which induce ambiguous times (such as a daylight saving time to standard time transition), the offset from before the transition is used when fold=0, and the offset after the transition is used when fold=1, for example:

>>> when = dt