Getting computer's UTC offset in Python

Question

In Python, how do you find what UTC time offset the computer is set to?

Answer 1

time.timezone:

import time  print -time.timezone 

It prints UTC offset in seconds (to take into account Daylight Saving Time (DST) see time.altzone:

is_dst = time.daylight and time.localtime().tm_isdst > 0 utc_offset = - (time.altzone if is_dst else time.timezone) 

where utc offset is defined via: "To get local time, add utc offset to utc time."

In Python 3.3+ there is tm_gmtoff attribute if underlying C library supports it:

utc_offset = time.localtime().tm_gmtoff 

Note: time.daylight may give a wrong result in some edge cases.

tm_gmtoff is used automatically by datetime if it is available on Python 3.3+:

from datetime import datetime, timedelta, timezone  d = datetime.now(timezone.utc).astimezone() utc_offset = d.utcoffset() // timedelta(seconds=1) 

To get the current UTC offset in a way that workarounds the time.daylight issue and that works even if tm_gmtoff is not available, @jts's suggestion to substruct the local and UTC time can be used:

import time from datetime import datetime  ts = time.time() utc_offset = (datetime.fromtimestamp(ts) -               datetime.utcfromtimestamp(ts)).total_seconds() 

To get UTC offset for past/future dates, pytz timezones could be used:

from datetime import datetime from tzlocal import get_localzone # $ pip install tzlocal  tz = get_localzone() # local timezone  d = datetime.now(tz) # or some other local date  utc_offset = d.utcoffset().total_seconds() 

It works during DST transitions, it works for past/future dates even if the local timezone had different UTC offset at the time e.g., Europe/Moscow timezone in 2010-2015 period.

Answer 2

gmtime() will return the UTC time and localtime() will return the local time so subtracting the two should give you the utc offset.

From https://pubs.opengroup.org/onlinepubs/009695399/functions/gmtime.html

The gmtime() function shall convert the time in seconds since the Epoch pointed to by timer into a broken-down time, expressed as Coordinated Universal Time (UTC).

So, despite the name gmttime, the function returns UTC.