Get time zone, daylight saving time, and base offset for any US ZIP code.

ZIP codes are up to date as of May 2024.

Ziptz is tested to work with the following versions of Ruby:

• Ruby 3.1.x, 3.2.x, 3.3.x

Add the gem to your Gemfile:

gem 'ziptz'

Get the time zone name for any ZIP code:

z = Ziptz.new
z.time_zone_name('97213') #=> "America/Los_Angeles"

Get the time zone offset for any ZIP code:

z.time_zone_offset('97213') #=> -28800

Note that offsets do not include daylight saving time.

Determine if the ZIP code uses Daylight Saving Time:

z.time_zone_uses_dst?('97213') #=> true

Get all the zip codes in a time zone:

z.zips('Pacific/Chuuk') #=> ["96942", "96943"]

• America/Adak
• America/Anchorage
• America/Boise
• America/Chicago
• America/Denver
• America/Detroit
• America/Indiana/Indianapolis
• America/Indiana/Knox
• America/Indiana/Marengo
• America/Indiana/Petersburg
• America/Indiana/Tell_City
• America/Indiana/Vevay
• America/Indiana/Vincennes
• America/Indiana/Winamac
• America/Juneau
• America/Kentucky/Louisville
• America/Kentucky/Monticello
• America/Los_Angeles
• America/Menominee
• America/Metlakatla
• America/New_York
• America/Nome
• America/North_Dakota/Beulah
• America/North_Dakota/Center
• America/North_Dakota/New_Salem
• America/Phoenix
• America/Puerto_Rico
• America/Sitka
• America/St_Thomas
• America/Yakutat
• Pacific/Chuuk
• Pacific/Guam
• Pacific/Honolulu
• Pacific/Kosrae
• Pacific/Kwajalein
• Pacific/Majuro
• Pacific/Pago_Pago
• Pacific/Palau
• Pacific/Pohnpei
• Pacific/Saipan
• Pacific/Wake

Note that APO/FPO zip codes will not return a known time zone offset.

If you would prefer raw data instead of a gem, see my ZIP Code Time Zones product on AWS Data Exchange to subscribe.

• APO, DPO, and FPO zip codes are no longer included, because they are non-geographic.
• Time zone offsets are now specified in seconds instead of hours.
• Time zone are now more granular. The full list of time zones is:
  • America/Adak
  • America/Anchorage
  • America/Boise
  • America/Chicago
  • America/Denver
  • America/Detroit
  • America/Indiana/Indianapolis
  • America/Indiana/Knox
  • America/Indiana/Marengo
  • America/Indiana/Petersburg
  • America/Indiana/Tell_City
  • America/Indiana/Vevay
  • America/Indiana/Vincennes
  • America/Indiana/Winamac
  • America/Juneau
  • America/Kentucky/Louisville
  • America/Kentucky/Monticello
  • America/Los_Angeles
  • America/Menominee
  • America/Metlakatla
  • America/New_York
  • America/Nome
  • America/North_Dakota/Beulah
  • America/North_Dakota/Center
  • America/North_Dakota/New_Salem
  • America/Phoenix
  • America/Puerto_Rico
  • America/Sitka
  • America/St_Thomas
  • America/Yakutat
  • Pacific/Chuuk
  • Pacific/Guam
  • Pacific/Honolulu
  • Pacific/Kosrae
  • Pacific/Kwajalein
  • Pacific/Majuro
  • Pacific/Pago_Pago
  • Pacific/Palau
  • Pacific/Pohnpei
  • Pacific/Saipan
  • Pacific/Wake

Time zone names now reflect standard tz-database names.

Copyright (c) 2015-2024 Keith Morrison <[email protected]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.