ClockJumper Research · Methodology
How the ClockJumper Research Dataset Is Built
Published July 2026 · ClockJumper Research
1 · City selection: the four gates
Cities enter the ClockJumper dataset through one of four inclusion gates: (1) classification as an Alpha-, Beta-, or Gamma-tier world city in the GaWC 2024 World Cities classification; (2) status as a principal services-delivery hub in a Kearney Global Services Location Index top-tier country, per national industry-association data (NASSCOM, IBPAP, ABSL, ANIS, IT Ukraine, VINASA, Argencon); (3) timezone-regime completeness — the most populous city of any inhabited UTC-offset regime (≥100,000 residents) not otherwise represented; or (4) inclusion in the publicly-released rankings of the Euromonitor Top 100 City Destinations Index 2025 (the composite Index and the associated international-arrivals ranking). Because Euromonitor’s full Top 100 is proprietary, this gate admits only cities named in Euromonitor’s public 2025 release; six destinations enter through this gate (Antalya, Kyoto, Macau, Mecca, Medina, Orlando). Cities appearing only in older Euromonitor editions are not admitted absent a verifiable current-edition source. Each city’s admitting gate is recorded in the dataset. Headline statistics are reported both city-weighted and regime-weighted, so roster composition cannot drive findings.
| Gate | Description | Cities admitted |
|---|---|---|
| G1 | GaWC 2024 Alpha/Beta/Gamma world city | 190 |
| G2 | Services-delivery hub (national industry-association data) | 12 |
| G3 | Timezone-regime completeness (≥100k) | 15 |
| G4 | Euromonitor Top 100 City Destinations 2025 | 6 |
| Total | 223 | |
Each city is credited to its first (primary) admitting gate.
2 · Computation
223 cities; 42 distinct (January, July) UTC-offset regimes; 24,753 unique city pairs; workday defined as 09:00–17:00 local; sample dates 2026-01-15 and 2026-07-15; all offsets computed from the IANA Time Zone Database at build time.
Build metadata: IANA Time Zone Database (via ICU 75.1) · build date 2026-07-05T11:08:34.003Z.
3 · Two ways to count: the dual-frame table
City-weighted answers “what does the average major-city pair look like”; regime-weighted gives each set of clock rules one vote and answers “what do the average clock rules look like.”
| Frame | January mean | January zero-overlap | July mean | July zero-overlap |
|---|---|---|---|---|
| City-weighted (24,753 pairs) | 3h04m | 29.5% | 3h14m | 28.2% |
| Regime-weighted (861 regime-pairs) | 2h34m | 36.8% | 2h36m | 36.8% |
The regime frame skews lower because many of the world’s 42 clock regimes are represented by geographically remote locations; the city frame skews higher because economic mass clusters in a handful of mutually close regimes. Neither is “correct” — they answer different questions, and we publish both.
4 · The regime map
All 42 distinct (January, July) UTC-offset regimes, with member counts and cities. 20 sole-representative regimes are admitted under Gate 3 (marked ★).
| Regime (Jan / Jul) | Cities | Members |
|---|---|---|
| -10 / -10 ★ | 1 | Honolulu |
| -9 / -8 ★ | 1 | Anchorage |
| -8 / -7 | 6 | Los Angeles, San Diego, San Francisco, San Jose (CA), Seattle, Vancouver |
| -7 / -7 ★ | 1 | Phoenix |
| -7 / -6 | 2 | Calgary, Denver |
| -6 / -6 | 8 | Guadalajara, Guatemala City, Managua, Mexico City, Monterrey, San José (Costa Rica), San Salvador, Tegucigalpa |
| -6 / -5 | 7 | Austin, Chicago, Dallas, Houston, Minneapolis, Nashville, St Louis |
| -5 / -5 | 6 | Bogota, Cali, Lima, Medellin, Panama City, Quito |
| -5 / -4 | 15 | Atlanta, Baltimore, Boston, Charlotte, Cleveland, Detroit, Miami, Montreal, New York, Orlando, Philadelphia, Pittsburgh, Tampa, Toronto, Washington DC |
| -4 / -4 | 2 | Caracas, Santo Domingo |
| -4 / -3 ★ | 1 | Halifax |
| -3:30 / -2:30 ★ | 1 | St. John's |
| -3 / -4 ★ | 1 | Santiago |
| -3 / -3 | 5 | Buenos Aires, Cordoba, Montevideo, Rio de Janeiro, Sao Paulo |
| -1 / -1 ★ | 1 | Praia |
| -1 / +0 ★ | 1 | Ponta Delgada |
| +0 / +0 ★ | 1 | Accra |
| +0 / +1 | 8 | Birmingham (UK), Bristol, Dublin, Edinburgh, Lisbon, London, Manchester, Porto |
| +1 / +1 | 3 | Casablanca, Lagos, Tunis |
| +1 / +2 | 41 | Amsterdam, Antwerp, Barcelona, Belgrade, Berlin, Bilbao, Bologna, Bratislava, Brussels, Budapest, Copenhagen, Dusseldorf, Frankfurt, Gdansk, Geneva, Hamburg, Katowice, Krakow, Ljubljana, Luxembourg, Lyon, Madrid, Marseille, Milan, Munich, Oslo, Paris, Poznan, Prague, Rome, Rotterdam, Stockholm, Stuttgart, Tirana, Turin, Valencia, Vienna, Warsaw, Wroclaw, Zagreb, Zurich |
| +2 / +2 | 2 | Cape Town, Johannesburg |
| +2 / +3 | 12 | Athens, Beirut, Bucharest, Cairo, Cluj-Napoca, Helsinki, Kyiv, Lviv, Nicosia, Riga, Sofia, Tel Aviv |
| +3 / +3 | 13 | Amman, Antalya, Dar es Salaam, Doha, Istanbul, Jeddah, Kampala, Kuwait City, Manama, Mecca, Medina, Nairobi, Riyadh |
| +3:30 / +3:30 ★ | 1 | Tehran |
| +4 / +4 | 6 | Abu Dhabi, Baku, Dubai, Muscat, Port Louis, Tbilisi |
| +4:30 / +4:30 ★ | 1 | Kabul |
| +5 / +5 | 4 | Almaty, Islamabad, Karachi, Lahore |
| +5:30 / +5:30 | 9 | Ahmedabad, Bangalore, Chennai, Colombo, Hyderabad, Kolkata, Mumbai, New Delhi, Pune |
| +5:45 / +5:45 ★ | 1 | Kathmandu |
| +6 / +6 ★ | 1 | Dhaka |
| +6:30 / +6:30 ★ | 1 | Yangon |
| +7 / +7 | 7 | Bangkok, Da Nang, Hanoi, Ho Chi Minh City, Jakarta, Phnom Penh, Surabaya |
| +8 / +8 | 39 | Beijing, Cebu, Changchun, Changsha, Chengdu, Chongqing, Dalian, Davao, Fuzhou, Guangzhou, Haikou, Hangzhou, Harbin, Hefei, Hong Kong, Jinan, Kuala Lumpur, Kunming, Labuan, Macau, Manila, Nanchang, Nanjing, Ningbo, Penang, Perth, Qingdao, Shanghai, Shenyang, Shenzhen, Singapore, Suzhou, Taipei, Taiyuan, Tianjin, Wuhan, Xiamen, Xian, Zhengzhou |
| +9 / +9 | 4 | Kyoto, Osaka, Seoul, Tokyo |
| +9:30 / +9:30 ★ | 1 | Darwin |
| +10 / +10 ★ | 1 | Brisbane |
| +10:30 / +9:30 ★ | 1 | Adelaide |
| +11 / +10 | 2 | Melbourne, Sydney |
| +11 / +11 ★ | 1 | Yuzhno-Sakhalinsk |
| +12 / +12 ★ | 1 | Suva |
| +13 / +12 | 2 | Auckland, Wellington |
| +13 / +13 ★ | 1 | Apia |
5 · Known limitations and notable omissions
Some notable cities do not appear in this dataset because they meet none of the four inclusion gates — among them Moscow, Addis Ababa, Ankara, Ottawa, Canberra, Brasília, Havana, and Reykjavik. Their absence reflects the measurement scope of our source frameworks, not a judgment of importance: GaWC classifies cities by advanced-producer-services connectivity, which excludes several national capitals and, in its 2024 edition, reflects the withdrawal of global services firms from Russia. No timezone regime is lost by these omissions — Gate 3 guarantees every inhabited offset regime remains represented. The complete list of excluded cities and the gate each failed is published in the data dictionary. All of these cities remain fully supported in the ClockJumper converter; they are excluded only from the research dataset.
Population-floor footnote
Regimes excluded by the ≥100k floor — Nuuk/Greenland (−2/−1, ~57k), Pago Pago (−11, ~44k), Kiritimati (+14, ~7k), Marquesas (−9:30), Chatham Islands (+13:45/+12:45), Lord Howe Island, Norfolk Island, Eucla, Easter Island (−5/−6), Adak, Miquelon (each under 10k).
6 · Sources
- GaWC World Cities 2024 (Globalization and World Cities Research Network, Loughborough University, October 2024).
- Kearney Global Services Location Index, 2023 edition (12th edition).
- National industry association sources (NASSCOM, IBPAP, ABSL, ANIS, IT Ukraine Association, VINASA, Argencon), accessed June 2026.
- Euromonitor International Top 100 City Destinations Index 2025 (December 2025).
- IANA Time Zone Database (IANA Time Zone Database (via ICU 75.1)).
7 · How this research was produced
This research was produced with AI assistance from Anthropic's Claude and OpenAI's ChatGPT. The dataset methodology, analysis, and written studies were developed by ClockJumper Research; all figures are computed deterministically from the published dataset and are independently verifiable via the downloadable CSV.
Roster reference: 223 cities in build.