Deal with Birtish summer time

Question

I have a date string 18 May 14:30 which corresponds to the British summertime (WEST or UTC+1). I would like to convert it to central Euopean (summer)time.

Here is my code

# from datetime import datetime
# from pytz import timezone

d = '18 May 14:30'
# Attempt 1
dd=datetime.strptime(d, '%d %b %H:%M').replace(year=datetime.now().year, tzinfo=timezone('WET'))
dd.astimezone(timezone('CET'))
# datetime.datetime(2019, 5, 18, 16, 30, tzinfo=<DstTzInfo 'CET' CEST+2:00:00 DST>)
# It should be 15:30, not 16:30

# Attempt 2
dd=datetime.strptime(d, '%d %b %H:%M').replace(year=datetime.now().year, tzinfo=timezone('WET'))
# Same result as above

# Attempt 3
dd=datetime.strptime(d, '%d %b %H:%M').replace(year=datetime.now().year, tzinfo=timezone('Etc/GMT-1'))
dd.astimezone(timezone('CET'))
# datetime.datetime(2019, 5, 18, 15, 30, tzinfo=<DstTzInfo 'CET' CEST+2:00:00 DST>)
# This works

So my problem in the third attempt I had to manually specify GMT-1 whereas CET automatically transforms to CEST. I hoped this would work identically for WET (to WEST).

Besides, what also confuses me is the fact that according to Wiki British summertime should be UTC +1 but I had to set GMT-1 (as GMT+1 returns 18:30).

Answer 1

In case it interests someone, I did manage to find a workaround

dd=datetime.strptime(d, '%d %b %H:%M').replace(year=datetime.now().year)
timezone('WET').localize(dd).astimezone(timezone('CET'))
# datetime.datetime(2019, 5, 18, 15, 30, tzinfo=<DstTzInfo 'CET' CEST+2:00:00 DST>)
# Correct result without having to specify the shift

# Let's check with another date (non-summertime)
d = '18 Jan 14:30'
dd=datetime.strptime(d, '%d %b %H:%M').replace(year=datetime.now().year)
timezone('WET').localize(dd).astimezone(timezone('CET'))
# datetime.datetime(2019, 1, 18, 15, 30, tzinfo=<DstTzInfo 'CET' CET+1:00:00 STD>)
# Yay!

It's not very elegant but at least it does the job.