Get Timezone from City in Python/Django
Solution 1
pytz
is a wrapper around IANA Time Zone Database (Olson database). It does not contain data to map an arbitrary city in the world to the timezone it is in.
You might need a geocoder such as geopy
that can translate a place (e.g., a city name) to its coordinates (latitude, longitude) using various web-services:
from geopy import geocoders # pip install geopy
g = geocoders.GoogleV3()
place, (lat, lng) = g.geocode('Singapore')
# -> (u'Singapore', (1.352083, 103.819836))
Given city's latitude, longitude, it is possible to find its timezone using tz_world, an efele.net/tz map / a shapefile of the TZ timezones of the world e.g., via postgis timezone db or pytzwhere
:
import tzwhere
w = tzwhere()
print w.tzNameAt(1.352083, 103.819836)
# -> Asia/Singapore
There are also web-services that allow to convert (latitude, longitude) into a timezone e.g., askgeo, geonames, see Timezone lookup from latitude longitude.
As @dashesy pointed out in the comment, geopy
also can find timezone (since 1.2):
timezone = g.timezone((lat, lng)) # return pytz timezone object
# -> <DstTzInfo 'Asia/Singapore' LMT+6:55:00 STD>
GeoNames also provides offline data that allows to get city's timezone directly from its name e.g.:
#!/usr/bin/env python
import os
from collections import defaultdict
from datetime import datetime
from urllib import urlretrieve
from urlparse import urljoin
from zipfile import ZipFile
import pytz # pip install pytz
geonames_url = 'http://download.geonames.org/export/dump/'
basename = 'cities15000' # all cities with a population > 15000 or capitals
filename = basename + '.zip'
# get file
if not os.path.exists(filename):
urlretrieve(urljoin(geonames_url, filename), filename)
# parse it
city2tz = defaultdict(set)
with ZipFile(filename) as zf, zf.open(basename + '.txt') as file:
for line in file:
fields = line.split(b'\t')
if fields: # geoname table http://download.geonames.org/export/dump/
name, asciiname, alternatenames = fields[1:4]
timezone = fields[-2].decode('utf-8').strip()
if timezone:
for city in [name, asciiname] + alternatenames.split(b','):
city = city.decode('utf-8').strip()
if city:
city2tz[city].add(timezone)
print("Number of available city names (with aliases): %d" % len(city2tz))
#
n = sum((len(timezones) > 1) for city, timezones in city2tz.iteritems())
print("")
print("Find number of ambigious city names\n "
"(that have more than one associated timezone): %d" % n)
#
fmt = '%Y-%m-%d %H:%M:%S %Z%z'
city = "Zurich"
for tzname in city2tz[city]:
now = datetime.now(pytz.timezone(tzname))
print("")
print("%s is in %s timezone" % (city, tzname))
print("Current time in %s is %s" % (city, now.strftime(fmt)))
Output
Number of available city names (with aliases): 112682
Find number of ambigious city names
(that have more than one associated timezone): 2318
Zurich is in Europe/Zurich timezone
Current time in Zurich is 2013-05-13 11:36:33 CEST+0200
Solution 2
there have been a lot of possible solutions proposed here and they're all a bit tedious to set up.
To make things quicker for the next person with this problem, I took the one from Will Charlton and made a quick python library out of it: https://pypi.python.org/pypi/whenareyou
from whenareyou import whenareyou
tz = whenareyou('Hamburg')
tz.localize(datetime(2002, 10, 27, 6, 0, 0))
Gets you datetime.datetime(2002, 10, 27, 6, 0, tzinfo=<DstTzInfo 'Europe/Berlin' CET+1:00:00 STD>)
.
This gets you a pytz object (tz
in the example) so you can use it pythonicly.
- It uses the google API
- Leaves daylight savings calculation to pytz, only one call per city, rest happens offline
- LRU caches the requests so you shouldn't hit the API limit easily
- Should also work with any address or anything google maps understands
Solution 3
The idea is to find lat/long coordinates for given city (or state) with one of geopy's geocoders, and get the appropriate time zone from the geocoder. Ex:
from datetime import datetime, timezone
from geopy import geocoders
# get the location by using one of the geocoders.
# GeoNames has a free option.
gn = geopy.geocoders.GeoNames(username='your-account-name')
loc = gn.geocode("California, USA")
# some geocoders can obtain the time zone directly.
# note: the geopy.timezone object contains a pytz timezone.
loc_tz = gn.reverse_timezone(loc.point)
# EXAMPLE: localize a datetime object
dt_UTC = datetime(2020, 11, 27, 12, 0, 0, tzinfo=timezone.utc)
dt_tz = dt_UTC.astimezone(loc_tz.pytz_timezone)
print(dt_tz, repr(dt_tz))
# 2020-11-27 04:00:00-08:00
# datetime.datetime(2020, 11, 27, 4, 0, tzinfo=<DstTzInfo 'America/Los_Angeles' PST-1 day, 16:00:00 STD>)
If the geocoder doesn't yield a time zone, you can use timezonefinder to attribute a time zone to given lat/long coordinates.
Solution 4
I think you're going to need to manually search the timezone database for the city you're looking for:
from pytz import country_timezones, timezone
def find_city(query):
for country, cities in country_timezones.items():
for city in cities:
if query in city:
yield timezone(city)
for tz in find_city('Zurich'):
print(tz)
(that's just a quick-and-dirty solution, it for instance doesn't try to match only the city-part of a timezone – try searching for Europe
, it does substring matches, doesn't search case-insensitive, etc.)
Solution 5
There is not trivial way of doing this, which is unfortunate. Geonames records a list of every city, along with its time zone name. This would be a god pick, but you will have to parse and build your own database around this, so you can easily find at any moment the time zone from a country/city pair.
Related videos on Youtube
super9
I work as a developer for a startup in Singapore. Messing around with iOS in my spare time.
Updated on July 09, 2022Comments
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super9 almost 2 years
Using
pytz
, I am able to get a list of timezones like so:>>> from pytz import country_timezones >>> print(' '.join(country_timezones('ch'))) Europe/Zurich >>> print(' '.join(country_timezones('CH'))) Europe/Zurich
Given that I am getting both Country and City fields from the user, how can I go about determining the timezone for the city?
-
robertklep almost 11 yearsYou mean you want to search the timezone database for a specific city and get its timezone? Or do you just want the timezone of (in this case)
Europe/Zurich
? -
super9 almost 11 yearsI want to search the timezone database for a specific city and get its timezone
-
jfs over 8 years
-
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jfs almost 11 yearsit should work by the list of supported cities is very small.
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jfs almost 11 yearsit doesn't work for most cities. Number of cities is much larger than number of timezones.
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robertklep almost 11 years@J.F.Sebastian OP wrote "I want to search the timezone database for a specific city", so I limited my solution to cities in the timezone database provided by
pytz
. -
jfs almost 11 yearsOP wrote "Given that I am getting both Country and City fields from the user, how can I go about determining the timezone for the city?" How likely do you think a user gives the city name that is also a part of a timezone name?
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robertklep almost 11 years@J.F.Sebastian hence my question in the comments: "You mean you want to search the timezone database...?".
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dashesy about 9 yearsI think some time has passed, it seems now
geopy
itself can find timezone:g.timezone(g.geocode('Singapore').point)
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jfs about 9 years@dashesy yes, it is now like other already mentioned online services in the answer.
.timezone()
method is available for 6 months now -
Ricky Levi almost 8 yearsa lot of cities are not found there ... London is easy, but other cities are simply not listed there ..
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Ciasto piekarz over 6 yearsthe only downside of offline data it takes good amount of storage space , and for those using hobby-dev or free tier of amazon this might not work, even the max redis memory available for free is 30MB on redis cloud
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Harry Moreno over 5 yearshere's a fully python 3 version on colab colab.research.google.com/drive/…
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Ruxi Zhang almost 5 yearsThis looks like a quite interesting module, but when I try it today it returns error. I was just using your example from README file. 50 latlong = cached_json_get( 51 LONG_LAT_URL.format(quote_plus(address)) ---> 52 )['results'][0]['geometry']['location'] 53 54 return get_tz(latlong['lat'], latlong['lng']) IndexError: list index out of range
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Ruxi Zhang almost 5 yearsLooks like I need to purchase google premium plan to have access to gmap data!
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BenjaminK almost 4 years@LasseSchuirmann Even your example gave me the error
ModuleNotFoundError: No module named 'dateutil'
if I installpython-dateutil
it gives meUnicodeDecodeError: 'charmap' codec can't decode byte 0x8d in position 2098: character maps to <undefined>
I really liked the idea of your program but sadly it seems to not work. -
Lasse Schuirmann almost 4 years@BenjaminK hey, sorry this was several years ago :/ I don't get your error, however it seems that the google API by now doesn't allow anonymous requests anymore. If you're looking to fix it, please check out github.com/aerupt/whenareyou , I'll be available to review any changes and perform a release if needed.
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Lasse Schuirmann almost 4 years@BenjaminK try the latest version from git, I just merged something that could help you. (I haven't tested it thoroughly, I don't have much time for open source stuff these days :/)
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Ricky Levi almost 4 yearsI received error:
ImportError: cannot import name '_normalize_host' from 'requests.packages.urllib3.util.url'
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Naveen Reddy Marthala almost 3 yearsfrom what I gather,
timezonefinder
works only with lats and longs. and geopy is down(as on Jul-1, 2PM IST), so haven't been able to register for a username. does anyone has an alternative? thanks. -
FObersteiner almost 3 years@NaveenKumar:
GeoNames
webservice is working as far as I can tell; not sure about other geocoders though. -
Naveen Reddy Marthala almost 3 yearsyes, it may be working, but i don't have an username to use. i get HTTP error when i try some dummy user name and geopy's website is down for me to be able to create an username.
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FObersteiner almost 3 years@NaveenKumar:
geopy
is just the package; see Geopy Is Not a Service. You'll need an account for a certain geocoding service.