How to convert local time string to UTC?

Question

How do I convert a datetime string in local time to a string in UTC time?

I\'m sure I\'ve done this before, but can\'t find it and SO will hopefull

Answer 1

This thread seems to be missing an option available since Python 3.6: datetime.astimezone(tz=None) can be used to get an aware datetime object representing local time (docs). This can then easily be converted to UTC.

from datetime import datetime, timezone
s = "2008-09-17 14:02:00"

# to datetime object:
dt = datetime.fromisoformat(s) # Python 3.7

# I'm on time zone Europe/Berlin; CEST/UTC+2 during summer 2008
dt = dt.astimezone()
print(dt)
# 2008-09-17 14:02:00+02:00

# ...and to UTC:
dtutc = dt.astimezone(timezone.utc)
print(dtutc)
# 2008-09-17 12:02:00+00:00

There is one caveat though, see astimezone(None) gives aware datetime, unaware of DST.