World Time Zone Map
Houston's position in the global time zone system
Houston is currently on CDT (UTC−5:00) — Daylight Saving Time active
All Time Zones Relative to Houston
| UTC Offset | Abbr | Major Cities | vs Houston |
|---|---|---|---|
| UTC−12 | Baker Island | Baker Island | −6h |
| UTC−11 | SST | American Samoa | −5h |
| UTC−10 | HAST | Honolulu | −4h |
| UTC−9 | AKST | Anchorage | −3h |
| UTC−8 | PST | Los Angeles, Seattle, Vancouver | −2h |
| UTC−7 | MST | Denver, Phoenix, Calgary | −1h |
| UTC−6 | CST | 📍 Houston, Chicago, Dallas, Mexico City | — |
| UTC−5 | EST | New York, Miami, Toronto, Lima | +1h |
| UTC−4 | AST | Santiago, Caracas, Halifax | +2h |
| UTC−3 | BRT | São Paulo, Buenos Aires | +3h |
| UTC−2 | FNT | Fernando de Noronha | +4h |
| UTC−1 | CVT | Cape Verde, Azores | +5h |
| UTC+0 | GMT | London, Accra, Reykjavik | +6h |
| UTC+1 | CET | Paris, Berlin, Madrid, Lagos | +7h |
| UTC+2 | EET | Cairo, Athens, Johannesburg | +8h |
| UTC+3 | MSK | Moscow, Istanbul, Riyadh | +9h |
| UTC+4 | GST | Dubai, Baku | +10h |
| UTC+5 | PKT | Karachi, Tashkent | +11h |
| UTC+5:30 | IST | Mumbai, Delhi, Bangalore | +11.5h |
| UTC+6 | BST | Dhaka, Almaty | +12h |
| UTC+7 | ICT | Bangkok, Jakarta, Hanoi | +13h |
| UTC+8 | SGT/CST | Singapore, Hong Kong, Shanghai, Perth | +14h |
| UTC+9 | JST/KST | Tokyo, Seoul | +15h |
| UTC+10 | AEST | Sydney, Melbourne, Brisbane | +16h |
| UTC+11 | SBT | Solomon Islands | +17h |
| UTC+12 | NZST | Auckland, Fiji | +18h |
* Offsets shown are for standard time. During daylight saving, some zones shift by +1 hour. Half-hour and 45-minute offsets (India, Nepal, etc.) are included where applicable.
United States Time Zones
Central (CT)
UTC−6/−5
Houston, Chicago, Dallas
📍 Houston's zoneMountain (MT)
UTC−7/−6
Denver, Phoenix, SLC
−1h from HoustonPlus Hawaii-Aleutian (UTC−10, no DST) and Alaska (UTC−9/−8). Arizona does not observe DST and stays on MST (UTC−7) year-round.
Understanding Time Zones
The world is divided into 24 primary time zones, each roughly 15 degrees of longitude wide. Time zones are measured as offsets from Coordinated Universal Time (UTC), which replaced Greenwich Mean Time (GMT) as the international standard in 1972. Houston, Texas sits in the Central Time Zone (UTC−6:00) during standard time and UTC−5:00 during daylight saving time.
The concept of standardized time zones was proposed by Canadian railway planner Sir Sandford Fleming in 1879 and adopted internationally in 1884 at the International Meridian Conference in Washington, D.C. Before this, each city kept its own local solar time, which made railroad scheduling chaotic.
Houston's Central Time Zone Position
Houston's position at approximately 95°W longitude places it squarely within the Central Time Zone, which spans roughly from 82.5°W to 97.5°W. This central position in the US gives Houston a strategic advantage for business: it overlaps with both the East Coast (only 1 hour difference) and the West Coast (2 hours), while maintaining morning overlap with European business hours.
The Central Time Zone is home to approximately 93 million Americans, making it the second-most-populated US time zone after Eastern. It covers states from Wisconsin and Illinois in the north through Texas to the Gulf of Mexico in the south.
Special Time Zone Cases
- India (UTC+5:30): Uses a unique half-hour offset, one of only a few countries to do so
- Nepal (UTC+5:45): The only country using a 45-minute offset
- China: Uses a single time zone (UTC+8) despite spanning 5 geographic zones
- Russia: Spans 11 time zones, from UTC+2 to UTC+12
- Arizona: Does not observe DST (except Navajo Nation), staying on MST year-round
- International Date Line: Runs through the Pacific Ocean at roughly 180° longitude
IANA Time Zone Database
Modern computers, phones, and servers use the IANA Time Zone Database (also called the tz database or Olson database) to determine local times. Houston is identified as America/Chicago in this system. Despite referencing Chicago, this identifier applies to the entire US Central Time Zone, including Houston, Dallas, San Antonio, and New Orleans. The database is maintained by a community of volunteers and updated several times per year to reflect political changes in time zone boundaries and DST rules.