'Python datetime.now in cygwin console is incorrect

If you could help me understand why: From Cygwin terminal:

This is correct:

$ date
Wed, Sep  2, 2020 11:19:07 PM

This is also correct:

$ date --utc
Wed, Sep  2, 2020  9:19:14 PM

Timezone is also correct:

$ echo $TZ
Europe/Zurich

But when ask for local time in Python3 from the same Cygwin terminal it shows this:

$ python
Python 3.8.5 (tags/v3.8.5:580fbb0, Jul 20 2020, 15:57:54) [MSC v.1924 64 bit (AM
D64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> datetime.now()
datetime.datetime(2020, 9, 2, 22, 20, 4, 339547)

The hour is wrong? It shows 22h20m4s but it should be 23h20h4s as shown previously.

What am I missing?

Thanks

python-3.xdatetimecygwin


Solution 1:[1]

you are using Windows Python and not Cygwin one.
The cygwin one matches with the rest of Cygwin programs

$ python3
Python 3.8.3 (default, May 23 2020, 15:50:53)
[GCC 9.3.0] on cygwin
Type "help", "copyright", "credits" or "license" for more information.
 >>> from datetime import datetime
>>> datetime.now()
datetime.datetime(2020, 9, 2, 23, 45, 26, 525415)
>>> quit()

 $ date
Wed, Sep  2, 2020 11:45:40 PM

Solution 2:[2]

… and likely reasons are explained here: https://stackoverflow.com/a/11655109 In short: cygwin sets TZ environment variable to the value which is not properly understood by msvc libc, so program built with visual C++ (like official non-cygwin python which was used above) and started from cygwin will use incorrect timezone for localtime.

unset TZ before starting such a program should help (but of course it will break cygwin-compiled programs). Not sure whether TZ="" python3 would suffice (empty variable is still variable…)

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 matzeri
Solution 2 Mekk

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