Oceania · Micronesia · Dependency
Current time in Guam
A single time zone at UTC+10:00.
Thursday, October 15, 2026
About Guam's time
A single time zone.
Guam uses a single time zone—Chamorro Standard Time (ChST) at UTC+10:00 year-round, with no daylight saving time. As a U.S. territory in the western Pacific, it shares the same time as the neighboring Northern Mariana Islands.
Major cities
Cities of Guam.
History
How Guam keeps time.
Guam has kept time at UTC+10:00 since 1901, when it replaced local mean time. During the Japanese occupation, from December 1941 to July 1944, the island ran on UTC+09:00, then returned to UTC+10:00.
Guam observed daylight saving time (UTC+11:00) in several years between 1959 and 1977 and has not changed its clocks since. In December 2000, U.S. federal law renamed its time zone from Guam Standard Time to Chamorro Standard Time (ChST); the offset itself did not change.
Did you know?
Things about Guam's time.
Guam’s location just west of the International Date Line creates an interesting quirk: while it shares the same calendar day as Australia and New Zealand, it is 15 hours ahead of U.S. Eastern Time in winter and 14 hours ahead during U.S. daylight saving time—making real-time communication with the U.S. mainland challenging.
Despite being a U.S. territory, Guam’s time zone aligns more closely with neighboring Micronesian islands and parts of Russia than with any continental U.S. state. This reflects its geographic reality rather than political boundaries.
Chamorro Standard Time (ChST) has no daylight saving adjustments, which simplifies scheduling. Because Guam lies in the tropics, sunrise shifts only modestly through the year, from about 5:50 AM in early June to about 6:50 AM in January.
Convert
Guam to the world's clocks.
Frequently asked questions
Common questions about Guam's time zone, daylight saving rules, and how to handle it in software. Can't find what you need? Email [email protected].
- What is the time difference between Guam and Washington, D.C.?
- Guam is 15 hours ahead of Washington, D.C. when D.C. is on standard time (UTC-5), and 14 hours ahead during U.S. daylight saving time (UTC-4). When it's 8 AM in D.C., it's 11 PM the same day in Guam in winter, or 10 PM in summer.
- Is there daylight saving time in Guam?
- No, Guam does not observe daylight saving time. Chamorro Standard Time (ChST) is UTC+10:00 year-round.
- Can I call my family in Guam during U.S. business hours?
- It’s generally not advisable. A 9 AM call from New York reaches Guam at 11 PM the same day during U.S. daylight saving time, or at midnight during U.S. standard time. Early morning or late evening calls from the U.S. mainland are better to catch Guam residents during their waking hours.
- Why doesn’t Guam follow U.S. time zones?
- Guam is geographically located in the western Pacific, far from the continental U.S. Its time zone reflects its position near the International Date Line and regional alignment with Micronesia, not U.S. domestic time zone logic.
- Does Guam ever change its clocks?
- No, there are no clock changes in Guam. The island stays on Chamorro Standard Time (UTC+10:00) all year.
- How does Guam’s time compare to nearby islands?
- Guam shares Chamorro Standard Time (UTC+10:00) with the Northern Mariana Islands. Nearby Federated States of Micronesia use UTC+11:00 or UTC+10:00 depending on location, while Palau uses UTC+9:00.
Source: IANA tzdb2026d · Reviewed
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