Explore Timezones with Python Pytz Library – Timezone List

Timezones play a crucial role in our interconnected world, where events, meetings and data are shared globally. Managing timezones correctly is essential to ensure that timestamps are accurate and consistent across different regions. Python’s pytz library is a powerful tool that simplifies working with timezones, offering a wide range of options to handle time-related operations. In this blog, we will explore pytz and its capabilities, including list of common timezones.

Understanding pytz

pytz is a Python library that provides access to the Olson timezone database, which includes comprehensive list of timezones from around the world. This library allows developers to work with timezones efficiently, addressing issues related to daylight saving time (DST), historical timezone changes, and more..

Common Timezones in pytz

Here is a list of some common timezones available in the pytz library for Python:

  1. pytz.UTC: Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks and time. It serves as a reference point for all other timezones.
  2. pytz.timezone('US/Eastern'): Eastern Time (ET) is commonly used in the eastern United States, including cities like New York and Washington, D.C.
  3. pytz.timezone('US/Pacific'): Pacific Time (PT) is prevalent on the west coast of the United States, covering cities like Los Angeles and San Francisco.
  4. pytz.timezone('Europe/London'): Greenwich Mean Time (GMT) is often used as a reference timezone, and it’s the same as UTC when there is no DST in effect.
  5. pytz.timezone('Europe/Paris'): Central European Time (CET) is observed in Central Europe, including cities like Paris, Berlin, and Rome.
  6. pytz.timezone('Asia/Tokyo'): Japan Standard Time (JST) is used in Japan and is nine hours ahead of UTC.
  7. pytz.timezone('Australia/Sydney'): Australian Eastern Time (AET) is observed in eastern Australia, including Sydney and Melbourne.
  8. pytz.timezone('India/Mumbai'): Indian Standard Time (IST) is used throughout India and is five and a half hours ahead of UTC.
  9. pytz.timezone('Africa/Cairo'): Eastern European Time (EET) is observed in parts of Eastern Europe and the Middle East, including Cairo and Athens.
  10. pytz.timezone('America/Mexico_City'): Central Standard Time (CST) is commonly used in Mexico and parts of Central America.

Working with pytz

Using pytz in your Python code is straightforward. You can convert datetime objects to different timezones, compare timestamps from different regions, and handle daylight saving time transitions effortlessly. Additionally, pytz allows you to access historical timezone information, which can be useful for applications that deal with historical data.

Here’s an example code snippet that demonstrates how to use pytz library to work with timezones, convert datetime objects, and handle daylight saving time transitions:

import datetime
import pytz

# Create a datetime object for a specific date and time
my_datetime = datetime.datetime(2023, 5, 15, 14, 30)

# Convert the datetime object to a specific timezone (e.g., New York, Eastern Time)
new_york_timezone = pytz.timezone('US/Eastern')
ny_datetime = new_york_timezone.localize(my_datetime)

# Convert the datetime object to another timezone (e.g., London, GMT)
london_timezone = pytz.timezone('Europe/London')
london_datetime = ny_datetime.astimezone(london_timezone)

# Print the original datetime and the converted datetime
print("Original Datetime:", my_datetime)
print("New York Datetime:", ny_datetime)
print("London Datetime:", london_datetime)

# Handling Daylight Saving Time (DST)
summer_datetime = datetime.datetime(2023, 7, 15, 14, 30)
ny_summer_datetime = new_york_timezone.localize(summer_datetime)
ny_winter_datetime = ny_summer_datetime - datetime.timedelta(days=180)

print("\nSummer Datetime (DST):", ny_summer_datetime)
print("Winter Datetime (Standard Time):", ny_winter_datetime)

In this code:

  1. We create a datetime object for a specific date and time (my_datetime).
  2. We use pytz.timezone to define two different timezones: New York (Eastern Time) and London (Greenwich Mean Time).
  3. We use localize and astimezone methods to convert my_datetime from the default system timezone to New York and then to London timezones.
  4. We demonstrate how pytz handles Daylight Saving Time (DST) by creating datetime objects in both summer and winter months for New York and observing the timezone transitions.

When you run this code, you’ll see the datetime values adjusted for the respective timezones and DST changes.


Timezone management is a critical aspect of developing applications that deal with time-related data. Python’s pytz library simplifies this task by providing a comprehensive list of timezones and tools to work with them effectively. By understanding and utilizing pytz, developers can ensure that their applications handle time-related operations accurately and consistently across different regions and timezones. So whether you”re scheduling meetings across continents or tracking historical events, pytz is an indispensable tool in your Python toolkit.