Weird timezone issue with pytz

Arthur B. picture Arthur B. · Jul 13, 2012 · Viewed 8.2k times · Source
>>> import pytz
>>> pytz.timezone('Asia/Hong_Kong')
<DstTzInfo 'Asia/Hong_Kong' LMT+7:37:00 STD>

A seven hour and 37 minute offset? This is a little strange, does anyone experience the same issue?

In fact I'm getting different behavior between

import pytz
from datetime import datetime
hk = pytz.timezone('Asia/Hong_Kong')

dt1 = datetime(2012,1,1,tzinfo=hk)
dt2 = hk.localize(datetime(2012,1,1))
if dt1 > dt2:
   print "Why?"

Answer

Mark Ransom picture Mark Ransom · Jul 13, 2012

Time zones and offsets change over the years. The default zone name and offset delivered when pytz creates a timezone object are the earliest ones available for that zone, and sometimes they can seem kind of strange. When you use localize to attach the zone to a date, the proper zone name and offset are substituted. Simply using the datetime constructor to attach the zone to the date doesn't allow it to adjust properly.