Technical Specifications & Standards
Official chronometric properties, ISO standards, and international database registry identifiers for Indochina Time:
Daylight Saving Time (DST) Transitions
⬆️ Spring Forward (Clocks Advance)
None (Tropical latitude near the equator maintains uniform day length)
⬇️ Fall Back (Clocks Return)
None
Observing Jurisdictions & Subdivisions
4 Sovereign NationsSovereign nations, administrative subdivisions, and regional territories officially operating under ICT:
Regional Subdivisions & Territory Details
Financial Markets & Trading Hours
Bangkok and Ho Chi Minh City serve as major regional manufacturing, tech assembly, and agricultural supply hubs, overlapping closely with Tokyo and Singapore trading hours.
Local Hours: 10:00 - 16:30 ICT
UTC Window: 01:30 - 09:30 UTC
Local Hours: 09:00 - 15:00 ICT
UTC Window: 01:30 - 09:30 UTC
Local Hours: 09:00 - 15:00 ICT
UTC Window: 01:30 - 09:30 UTC
Local Hours: 08:00 - 15:00 ICT
UTC Window: 01:30 - 09:30 UTC
Major Cities in ICT
Primary metropolitan centers and financial hubs observing this time zone:
Adoption History & Astronomical Facts
Year Established: 1920
Adopted across Thailand in 1920 under King Rama VI, setting national standard time to the 105th meridian east. French Indochina had previously aligned Vietnam, Cambodia, and Laos to UTC+7 in 1911. During the Vietnam War, North Vietnam maintained UTC+7 while South Vietnam switched to UTC+8; upon reunification in 1975, UTC+7 was restored across all of Vietnam.
Western Indonesia (including Jakarta and Sumatra) also operates on UTC+7 under the local name Waktu Indonesia Barat (WIB), meaning Bangkok, Hanoi, and Jakarta share the exact same clock time without any borders dividing their standard time.
Frequently Asked Questions about ICT
Which countries use Indochina Time?
Indochina Time (ICT, UTC+7) is observed across Thailand, Vietnam, Cambodia, and Laos. Western Indonesia also operates on the same UTC+7 offset under the abbreviation WIB.
Does Bangkok observe Daylight Saving Time?
No. Thailand and all neighboring Indochina nations stay on UTC+7 year-round because tropical daylight hours vary by less than 45 minutes between winter and summer.
What is the time difference between Bangkok and Singapore?
Singapore (SGT, UTC+8) is one hour ahead of Bangkok, Hanoi, and Phnom Penh (ICT, UTC+7).