Wrong dst() value on a historical time in Amsterdam

Bug #1497619 reported by Alexander Belopolsky on 2015-09-19
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
pytz
Undecided
Unassigned

Bug Description

>>> ams = pytz.timezone('Europe/Amsterdam')
>>> ams.localize(datetime(1940,7,1)).dst() // timedelta(minutes=1)
100
>>> ams.localize(datetime(1940,7,1)).tzname()
'CEST'

The value 100 minutes returned by dst() is incorrect because CEST summer time shift is the usual 60 min, not 100. What happened here was that Amsterdam switched to CEST from NET, not CET on 1940-05-16. Therefore, on 1940-05-16 the standard time offset changed, but DST adjustment remained the same.

To post a comment you must log in.
This report contains Public information  Edit
Everyone can see this information.

Other bug subscribers