How to get the common name for a pytz timezone eg. EST/EDT for America/New_York

Question

Given a pytz timezone for a particular user(calculated from his offset), i want to display the common name for that timezone. I'm assuming people are more accustomed to seeing EST or PST instead of spelled out like America/NewYork.

Does pytz give me those standard names somewhere, or will i have to manually do this via a table? This could potentially get messy, since for example places are EST in a season and shift to showing EDT during others.

Solution 1

Given a pytz timezone for a particular user(calculated from his offset), i want to display the common name for that timezone. I'm assuming people are more accustomed to seeing EST or PST instead of spelled out like America/NewYork.

If you need this derived from a datetime object localized with pytz...

>>> import pytz as tz
>>> from datetime import datetime as dt
>>> CT = tz.timezone('America/Chicago')
>>>
>>> summer_day = dt(2010, 7, 4, 0, 1, 1)
>>> bar = CT.localize(summer_day, is_dst=None)
>>> bar.tzname()
'CDT'
>>>
>>> christmas = dt(2010, 12, 25, 0, 1, 1)
>>> foo = CT.localize(christmas, is_dst=None)
>>> foo.tzname()
'CST'
>>> 

Solution 2

You can use the tzname() method of tzinfo instances:

>>> tz = timezone('America/St_Johns')
>>> normal = datetime(2009, 9, 1)
>>> tz.tzname(normal, is_dst=False)
'NDT'

Solution 3

If you are looking for the abbreviations then there are a few ways that come to mind.

First would be:

>>> from pytz import timezone
>>> eastern = timezone('US/Eastern')
>>> eastern._tzname
'EST'

Although since that references a property with the preceding single underscore it may be considered private and might not be the best place to grab it. The other would be from a localized datetime object.

>>> from datetime import datetime
>>> loc_dt = eastern.localize(datetime.now())
>>> loc_dt.strftime('%Z')
'EST'

Solution 4

This may not have been around when this question was originally written, but here is a snippet to get the time zone official designation:

>>> eastern = timezone('US/Eastern')
>>> eastern.zone
'US/Eastern'

Further, this can be used with a non-naive datetime object (aka a datetime where the actual timezone has been set using pytz.<timezone>.localize(<datetime_object>) or datetime_object.astimezone(pytz.<timezone>) as follows:

>>> import datetime, pytz
>>> todaynow = datetime.datetime.now(tz=pytz.timezone('US/Hawaii'))
>>> todaynow.tzinfo # turned into a string, it can be split/parsed
<DstTzInfo 'US/Hawaii' HST-1 day, 14:00:00 STD>
>>> todaynow.strftime("%Z")
'HST'
>>> todaynow.tzinfo.zone
'US/Hawaii'

This is, of course, for the edification of those search engine users who landed here. ... See more at the pytz module site.

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Comments

[jfs]

.localize may return wrong result if input naive datetime is ambiguous or non-existent e.g., during DST transitions. Use is_dst=None to assert that input time is unambiguous.

[jfs]

eastern.localize(datetime.now()) might give you a wrong result during DST transitions, use datetime.now(eastern) instead.

[summerbulb]

Is there a way to go back from 'CDT' to a timezone object with 'America/Chicago' timezone?