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from_timestamp fails with timestamps earlier than 12h before unix epoch #956
Description
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I am on the latest Pendulum version.
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I have searched the issues of this repo and believe that this is not a duplicate.
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OS version and name: Win11
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Pendulum version: 3.2.0
Issue
pendulum.from_timestamp() throws OSError when attempting to convert a timestamps earlier than 12h before the unix epoch.
>>> pendulum.from_timestamp(-43200)
DateTime(1969, 12, 31, 12, 0, 0, tzinfo=Timezone('UTC'))
>>> pendulum.from_timestamp(-43201)
Traceback (most recent call last):
File "<python-input-5>", line 1, in <module>
from_timestamp(-43201)
~~~~~~~~~~~~~~^^^^^^^^
File "C:\sst\reportsgenservice\.venv\Lib\site-packages\pendulum\__init__.py", line 290, in from_timestamp
dt = _datetime.datetime.fromtimestamp(timestamp, tz=UTC)
OSError: [Errno 22] Invalid argumentHowever, pendulum supports these dates without issues, for instance when parsing 0 dates from a database:
>>> pendulum.parse('1900-01-01')
DateTime(1900, 1, 1, 0, 0, 0, tzinfo=Timezone('UTC'))Current workaround is to substract negative timestamps to an unix epoch datetime instance:
>>> pendulum.from_timestamp(0).add(seconds=-43201)
DateTime(1969, 12, 31, 11, 59, 59, tzinfo=Timezone('UTC'))
Activity
[-]`from_timestamp` fails with timestamps more than 12h earlier before unix epoch[/-][+]`from_timestamp` fails with timestamps earlier than 12h before unix epoch[/+]parinporecha commentedon Apr 22, 2026
This has been addressed upstream in python/cpython#143463, so on Python 3.15+ the underlying stdlib behavior should be corrected.
I opened #962 because Pendulum may still want to handle this itself for currently supported Python versions, rather than only benefiting once users move to 3.15+. Totally fine either way, I'll leave that decision to the maintainers.