Python datetime conversions from one local timezone to another (+ bonus DST's)

Question

I'm having some trouble understanding why I'm getting the results I'm getting.

What I wanted to try:

1. Take two timezones, one that uses DST and one that doesn't. ex: Romania (dst) and Venezuela(no dst).

2. For the timezone that has dst, create two datetimes. One in the interval of the dst, and one that isn't. Romania DST interval (4-10 / April-October). Ex:

   from datetime import datetime
   from pytz import timezone
   
   tz1 = timezone('Europe/Bucharest')
   tz2 = timezone('America/Caracas')
   
   date1 = datetime(2016, 5, 5, 5, 0, 0, tzinfo=tz1)  # its in the dst interval (5 o'clock, summer - dst)
   date1 = datetime(2016, 12, 5, 5, 0, 0, tzinfo=tz1)  # isn't in the dst interval (5 o'clock, winter - no dst)
   
   x = date1.astimezone(tz2)
   y = date2.astimezone(tz2) 
   

3. Shouldn't x and y have different hours? Because date1 is in the DST interval, so 5 o'clock should mean a different hour than 5 o'clock in date2 when the datetime isn't in the DST interval.

Yet, both x and y have the same hour when converted to a no DST timezone.

Thanks for any explanations you can spare.

Answer 1

You can't use the datetime constructor to use a pytz timezone, you must use localize:

date1 = tz1.localize(datetime(2016, 5, 5, 5, 0, 0))
date2 = tz1.localize(datetime(2016, 12, 5, 5, 0, 0))

From the documentation:

Unfortunately using the tzinfo argument of the standard datetime constructors ‘‘does not work’’ with pytz for many timezones.