Cisco Clock Timezone Configuration

This article provides sample Cisco configuration commands for popular cities using “clock timezone” and “clock summer-time” commands. It also aggregates information about different time zones and their daylight saving dates.

Many services are dependent on the clock and time zone configuration on Cisco devices. Services such as certificate validity checks, logging are the obvious ones. The other examples include time-based ACLs or scheduled tasks that can cause outages during the daylight saving changes. The daylight savings rules are also changing time after time.

Time Zones and Daylight Settings

The time zone represents an area or region that observes the same time. Coordinated Universal Time (UTC) is the reference time. Time zones are expressed as an offset from it. Offset can be either negative or positive represented in a number of hours and in some cases in minutes.

Some regions observe daylight savings time when clocks are adjusted twice a year so there is an extra hour of daylight in the evening during summer. There are more daylight hours in summer than during winter. The difference is more noticeable when moving away from the equator. The adjustment is done in spring by moving clocks forward (spring forward) and then reversed in autumn by moving clocks back (fall back). Note that summer starts in December in some of the countries in the Southern hemisphere.

Time Configuration on Cisco devices

We recommend using NTP to ensure that time is accurately synchronized. NTP server sends time information in UTC, so it is important to set the correct time zone.

If manual clock settings are in use, the router assumes that the time is specified in the router’s local time zone, which is UTC by default. Therefore, the time zone settings should be configured before setting the clock manually, as otherwise, it will need to be re-adjusted after the router applies time zone configuration.

The following paragraphs show how to configure the correct time zone and daylight savings settings on the device.

To specify time zone and daylight settings two commands are used:

R1(config)#clock ?        
   summer-time     Configure summer (daylight savings) time
   timezone        Configure time zone

Time zone configuration requires only 2 parameters:

clock timezone zone hours-offset [minutes-offset]

Summer-time configuration can be either recurring or date-specific:

clock summer-time zone recurring [week day month hh:mm week day month hh:mm [offset]]
 clock summer-time zone date date month year hh:mm date month year hh:mm [offset]

Time Configuration on Cisco devices

The easiest way to lookup information is by navigating to the timeanddate.com website and browsing to the world clock page.

Then find the city name and click on it. Select the Time Zone button and it will display abbreviation and up-to-date information on when DST starts.

Below are the configuration samples for some of the popular cities with updated daylight information as of March 2020.

North America

CityCommand
Honolulu, US# Hawaii Standard Time
clock timezone HST -10
Vancouver, Canada# Pacific Standard Time
clock timezone PST -8

# Pacific Daylight Time
clock summer-time PDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
Los Angeles, US
San Francisco, US
Las Vegas, US
Seattle, US
# Pacific Standard Time
clock timezone PST -8

# Pacific Daylight Time
clock summer-time PDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
Mexico City, Mexico# Central Standard Time
clock timezone CST -6

# Central Daylight Time
clock summer-time CDT recurring 1 Sun Apr 2:00 1 Sun Nov 2:00
Denver, US# Mountain Standard Time
clock timezone MST -7

# Mountain Daylight Time
clock summer-time MDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
Cancun, Mexico# Eastern Standard Time
clock timezone EST -5
Panama, Panama# Eastern Standard Time
clock timezone EST -5
New Orleans, US
Kansas City, US
Austin, US
Dallas, US
Milwaukee, US
# Central Standard Time
clock timezone CST -6

# Central Daylight Time
clock summer-time CDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
Ottawa, Canada
Ontario, Canada
Montreal, Canada
Quebec, Canada
# Eastern Standard Time
clock timezone EST -5

# Eastern Daylight Time
clock summer-time EDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
Havana, Cuba# Cuba Standard Time
clock timezone EST -5

# Cuba Daylight Time
clock summer-time EDT recurring 2 Sun Mar 2:00 1 Sun Nov 1:00
Washington DC, US
Florida, US
Tampa, US
Atlanta, US
Indianapolis, US
Louisville, US
Baltimore, US
Boston, US
Michigan, US
New York, US
Philadelphia, US
Pittsburgh, US
Portsmouth, US
# Eastern Standard Time
clock timezone EST -5

# Eastern Daylight Time
clock summer-time EDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
Halifax, Canada# Atlantic Standard Time
clock timezone AST -4

# Atlantic Daylight Time
clock summer-time ADT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00

Table 1. North America Cities and Cisco Timezone Configuration Commands

South America

CityCommand
Bogota, Colombia# Colombia Time
clock timezone COT -5
Lima, Peru# Peru Time
clock timezone PET -5
Santa Cruz, Bolivia# Bolivia Time
clock timezone BOT -4
Caracas, Venezuela# Venezuelan Standard Time
clock timezone VET -4
Buenos Aires, Argentina
Santa Fe, Argentina
# Argentina Time
clock timezone ART -3
Brasilia, Brazil
Rio de Janeiro, Brazil
Sao Paulo, Brazil
# Brasilia Time
clock timezone BRT -3
Asuncion, Paraguay# Paraguay Time
clock timezone PYT -4

# Paraguay Summer Time
clock summer-time PYST recurring 1 Sun Oct 0:00 last Sun Oct 0:00
Montevideo, Uruguay# Uruguay Time
clock timezone UYT -3

Table 2. South America Cities and Cisco Timezone Configuration Commands

Europe

CityCommand
Reykjavik, Iceland# Greenwich Mean Time
clock timezone GMT
Dublin, Ireland# Greenwich Mean Time
clock timezone GMT

# Irish Standard Time (Daylight saving)
clock summer-time IST recurring last Sun Mar 1:00 last Sun Oct 2:00
Lisbon, Portugal
Porto, Portugal
# Western European Time
clock timezone WET

# Western European Summer Time
clock summer-time WEST recurring last Sun Mar 1:00 last Sun Oct 2:00
Birmingham, UK
Bristol, UK
Leeds, UK
Liverpool, UK
London, UK
Manchester, UK
Belfast, UK
Edinburgh, UK
Glasgow, UK
# Greenwich Mean Time
clock timezone GMT

# British Summer Time
clock summer-time BST recurring last Sun Mar 1:00 last Sun Oct 2:00
Tirana, Albania
Salzburg, Austria
Vienna, Austria
Brussels, Belgium
Sarajevo, Bosnia-Herzegovina
Zagreb, Croatia
Prague, Czechia
Copenhagen, Denmark
Strasbourg, France
Paris, France
Versailles, France
Toulouse, France
Marseille, France
Stuttgart, Germany
Munich, Germany
Berlin, Germany
Hamburg, Germany
Frankfurt, Germany
Hannover, Germany
Dortmund, Germany
Leipzig, Germany
Gibraltar, Gibraltar
Budapest, Hungary
Naples, Italy
Turin, Italy
Venice, Italy
Amsterdam, Netherlands
The Hague, Netherlands
Oslo, Norway
Krakow, Poland
Warsaw, Poland
Belgrade, Serbia
Ljubljana, Slovenia
Barcelona, Spain
Ibiza, Spain
Madrid, Spain
Stockholm, Sweden
Bern, Switzerland
Geneva, Switzerland
Lugano, Switzerland
Vatican City, Vatican City State
# Central European Time
clock timezone CET +1

# Central European Summer Time
clock summer-time CEST recurring last Sun Mar 2:00 last Sun Oct 3:00
Plovdiv, Bulgaria
Sofia, Bulgaria
Tallinn, Estonia
Helsinki, Finland
Athens, Greece
Riga, Latvia
Vilnius, Lithuania
Bucharest, Romania
Kyiv, Ukraine
Odesa, Ukraine
# Eastern European Time
clock timezone EET +2

# Eastern European Summer Time
clock summer-time EEST recurring last Sun Mar 3:00 last Sun Oct 4:00
Kaliningrad, Russia# Eastern European Time
clock timezone EET +2
Minsk, Belarus
Bryansk, Russia
Sochi, Russia
Moscow, Russia
Saint-Petersburg, Russia
# Moscow Standard Time
clock timezone MSK +3

Table 3. Europe Cities and Cisco Timezone Configuration Commands

Asia

CityCommand
Jerusalem, Israel
Tel Aviv, Israel
# Israel Standard Time
clock timezone IST +2

# Israel Daylight Time
clock summer-time IDT recurring last Sun Mar 2:00 last Sun Oct 2:00
Beirut, Lebanon# Eastern European Time
clock timezone EET +2

# Eastern European Summer Time
clock summer-time EEST recurring last Sun Mar 0:00 last Sun Oct 0:00
Baghdad, Iraq
Kuwait City, Kuwait
Doha, Qatar
Riyadh, Saudi Arabia
# Arabia Standard Time
clock timezone AST +3
Istanbul, Turkey# Turkey Time
clock timezone TRT +3
Tbilisi, Georgia# Georgia Standard Time
clock timezone GET +4
Yerevan, Armenia# Armenia Time
clock timezone AMT +4
Baku, Azerbaijan# Azerbaijan Time
clock timezone AZT +4
Dubai, United Arab Emirates# Gulf Standard Time
clock timezone GST +4
Kabul, Afghanistan# Afghanistan Time
clock timezone AFT +4 30
Tehran, Iran# Iran Standard Time
clock timezone IRST +3 30

# Iran Daylight Time 2020
clock summer-time IRDT date 21 Mar 2020 0:00 21 Sep 2020 0:00
# Iran Daylight Time 2021-2023
clock summer-time IRDT date 22 Mar 2021 0:00 22 Sep 2021 0:00
clock summer-time IRDT date 22 Mar 2022 0:00 22 Sep 2022 0:00
clock summer-time IRDT date 22 Mar 2023 0:00 22 Sep 2023 0:00
Islamabad, Pakistan
Karachi, Pakistan
Lahore, Pakistan
# Pakistan Standard Time
clock timezone PKT +5
Ufa, Russia
Chelyabinsk, Russia
Yekaterinburg, Russia
# Yekaterinburg Time
clock timezone YEKT +5
Dushanbe, Tajikistan# Tajikistan Time
clock timezone TJT +5
Ashgabat, Turkmenistan# Turkmenistan Time
clock timezone TMT +5
Tashkent, Uzbekistan# Uzbekistan Time
clock timezone UZT +5
Delhi, India
New Delhi, India
Bangalore, India
Mumbai, India
Kolkata, India
Colombo, Sri Lanka
# India Standard Time
clock timezone IST +5 30
Kathmandu, Nepal# Nepal Time
clock timezone NPT +5 45
Dhaka, Bangladesh# Bangladesh Standard Time
clock timezone BST +6
Almaty, Kazakhstan
Nursultan, Kazakhstan
# Alma-Ata Time
clock timezone ALMT +6
Bishkek, Kyrgyzstan# Kyrgyzstan Time
clock timezone KGT +6
Omsk, Russia# Omsk Standard Time
clock timezone OST +6
Phnom Penh, Cambodia
Hanoi, Vietnam
Ho Chi Minh, Vietnam
# Indochina Time
clock timezone ICT +7
Jakarta, Indonesia# Western Indonesian Time
clock timezone WIB +7
Novosibirsk, Russia# Novosibirsk Time
clock timezone NOVT +7
Beijing, China
Guangzhou, China
Shenzhen, China
Harbin, China
Nanjing, China
Shanghai, China
Chengdu, China
Lhasa, China
Hangzhou, China
Taipei, Taiwan
# China Standard Time
clock timezone CST +7
Hong Kong, Hong Kong# Hong Kong Time
clock timezone HKT +7
Kuala Lumpur, Malaysia# Malaysia Time
clock timezone MYT +8
Manila, Philippines# Philippine Time
clock timezone PHT +8
Irkutsk, Russia# Irkutsk Time
clock timezone IRKT +8
Singapore, Singapore# Singapore Time
clock timezone SGT +8
Kyoto, Japan
Osaka, Japan
Sapporo, Japan
Tokyo, Japan
Yokohama, Japan
# Japan Standard Time
clock timezone JST +9
Chita, Russia
Yakutsk, Russia
# Yakutsk Time
clock timezone YAKT +9
Busan, South Korea
Daegu, South Korea
Incheon, South Korea
Seoul, South Korea
# Korea Standard Time
clock timezone KST +9
Vladivostok, Russia# Vladivostok Time
clock timezone VLAT +10

Table 4. Asia Cities and Cisco Timezone Configuration Commands

Africa

CityCommand
Bissau, Guinea-Bissau
Monrovia, Liberia
Timbuktu, Mali
Dakar, Senegal
# Greenwich Mean Time
clock timezone GMT
Algiers, Algeria
Constantine, Algeria
Tunis, Tunisia
# Central European Time
clock timezone CET +1
Kinshasa, Congo
Lagos, Nigeria
# West Africa Time
clock timezone WAT +1
Casablanca, Morocco
Marrakech, Morocco
Tangier, Morocco
# Western European Time
clock timezone WET

# Western European Summer Time 2020-21
clock summer-time WEST date 9 Jun 2019 2:00 19 Apr 2020 Apr 3:00
clock summer-time WEST date 24 May 2020 2:00 11 Apr 2021 Apr 3:00
Alexandria, Egypt
Cairo, Egypt
Tobruk, Libya
Tripoli, Libya
# Eastern European Time
clock timezone EET +2
Cape Town, South Africa
Johannesburg, South Africa
Pretoria, South Africa
# South Africa Standard Time
clock timezone SAST +2
Khartoum, Sudan
Port Sudan, Sudan
# Central Africa Time
clock timezone CAT +2
Addis Ababa, Ethiopia
Mombasa, Kenya
Mogadishu, Somalia
Zanzibar City, Tanzania
# Eastern Africa Time
clock timezone EAT +3

Table 5. Africa Cities and Cisco Timezone Configuration Commands

Australia/Pacific

CityCommand
Perth, Australia# Australian Western Standard Time
clock timezone AWST +8
Darwin, Australia# Australian Central Standard Time
clock timezone ACST +9 30

Brisbane, Australia
Cairns, Australia
# Australian Eastern Standard Time
clock timezone AEST +10
Adelaide, Australia# Australian Central Standard Time
clock timezone ACST +9 30

# Australian Central Daylight Time
clock summer-time ACDT recurring 1 Sun Oct 2:00 1 Sun Apr 3:00
Canberra, Australia
Sydney, Australia
Hobart, Australia
Melbourne, Australia
# Australian Eastern Standard Time
clock timezone AEST +10

# Australian Eastern Daylight Time
clock summer-time AEDT recurring 1 Sun Oct 2:00 1 Sun Apr 3:00
Noumea, New Caledonia# New Caledonia Time
clock timezone NCT +11
Port Vila, Vanuatu# Vanuatu Time
clock timezone VUT +11
Auckland, New Zealand
Christchurch, New Zealand
Wellington, New Zealand
# New Zealand Standard Time
clock timezone NZST +12

# New Zealand Daylight Time
clock summer-time NZDT recurring last Sun Sep 2:00 1 Sun Apr 3:00

Table 6. Australia/Pacific Cities and Cisco Timezone Configuration Commands

Reference Information

Alphabetically sorted list of time zone abbreviations:

https://www.timeanddate.com/time/zones/

IANA supports the time zone database (https://www.iana.org/time-zones) and at the time of this blog post writing the latest one is 2019c release. To receive updates on time zone database updates, you can subscribe to the IANA’s mailing list (https://mm.icann.org/mailman/listinfo/tz-announce).