HST — Hawaii Standard Time
See what HST means, where it is used, how it relates to HDT, and compare UTC-10 with other time zones.
Countries: United States
How to Convert HST to Other Time Zones
Open the HST converter page: Visit https://www.xconvert.com/time-converter/hst-time-zone to open the visual comparison grid with Hawaii Standard Time (HST) pre-loaded. This page is useful when you are scheduling a call with a client in Honolulu, coordinating hotel check-in timing for a trip to Oahu or the Big Island, or lining up remote work with teams on the U.S. mainland and in Asia-Pacific.
Add comparison cities: Click “+ Add City” and search for cities such as Los Angeles, New York, and Tokyo to compare HST against major business and travel hubs. These are practical choices because Hawaii frequently connects with the U.S. West Coast for tourism and logistics, with New York for finance and corporate coordination, and with Tokyo for airline, hospitality, and Pacific-region business planning.
Select a time range on the grid: Click “Select” if needed, then drag across the HST row to highlight a meeting window, such as 9:00 AM to 11:00 AM HST. That same range converts to 12:00 PM to 2:00 PM in Los Angeles during Pacific Daylight Time, 3:00 PM to 5:00 PM in New York during Eastern Daylight Time, and 4:00 AM to 6:00 AM the next day in Tokyo, which quickly shows whether a Honolulu morning meeting works for mainland colleagues but is too early for Japan.
Export and share the result: After selecting the time range, use the export options shown on the page: ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is especially useful if you are sending a confirmed meeting slot to a distributed team, sharing a hotel pickup time with travelers, or creating a calendar event so everyone sees the appointment automatically in their own local time zone.
About Hawaii Standard Time (HST)
HST stands for Hawaii Standard Time. Its exact offset is UTC−10:00, meaning local time in HST is 10 hours behind Coordinated Universal Time; when it is 12:00 UTC, it is 2:00 AM HST.
Hawaii Standard Time is used in the United States, primarily across the state of Hawaii. Principal cities operating on HST include Honolulu, East Honolulu, Pearl City, Hilo, and Kailua; Honolulu alone has a population of roughly 350,000, while the urbanized Oahu region is the state’s main center for government, tourism, shipping, and military operations.
Because Hawaii is geographically isolated in the central Pacific, HST is important for industries with strong long-distance coordination needs. Airlines, hotels, cruise operators, defense agencies, and remote teams often compare HST with Pacific Time, Eastern Time, Japan Standard Time, and Australia/New Zealand time zones to manage bookings, handoffs, and customer support coverage.
The counterpart abbreviation listed for HST is HDT, which stands for Hawaii Daylight Time. In practice, modern Hawaii does not currently observe daylight saving time, so HST remains the year-round civil time used across the state; HDT is mainly a historical or reference term rather than a currently active seasonal clock in Hawaii.
HST shares the same UTC−10:00 offset with several other abbreviations, including CKT (Cook Island Time), TAHT (Tahiti Time), and W in military time notation. Even though the numeric offset is the same, these abbreviations refer to different regions, so travelers and businesses should check the city or region label rather than relying only on the offset.
HST and Daylight Saving Time
Hawaii Standard Time is one of the few U.S. time zones that does not currently switch for daylight saving time. The offset stays fixed at UTC−10:00 throughout the entire year, so there is no spring forward and no fall back in Honolulu, Hilo, Kailua, Pearl City, or East Honolulu.
For the current year, 2026, HST has no daylight saving transition dates. While most of the continental United States changes clocks on March 8, 2026 and November 1, 2026, Hawaii does not participate, which means the time difference between Hawaii and mainland U.S. cities changes seasonally even though Hawaii’s own clocks never move.
This creates a practical scheduling effect. For example, Hawaii is 2 hours behind Los Angeles when California is on Pacific Standard Time (UTC−8), but 3 hours behind Los Angeles when California is on Pacific Daylight Time (UTC−7); similarly, Hawaii is 5 hours behind New York during Eastern Standard Time and 6 hours behind New York during Eastern Daylight Time. If it is 9:00 AM in Honolulu, it is 11:00 AM in Los Angeles in winter but 12:00 PM in Los Angeles in summer.
The abbreviation HDT refers to Hawaii Daylight Time, but there is no active annual switch from HST to HDT in modern Hawaii. If you see HDT in older references, archived systems, or historical discussions, treat it as a legacy designation rather than the current legal time used in the state.
Frequently Asked Questions
What does HST stand for?
HST stands for Hawaii Standard Time. It is the standard civil time used in the U.S. state of Hawaii and operates at UTC−10:00 all year, which makes it one of the westernmost regularly used U.S. time zones.
Is HST the same as HDT?
No, HST and HDT are not the same abbreviation. HST means Hawaii Standard Time at UTC−10:00, while HDT means Hawaii Daylight Time, a daylight-saving counterpart that is largely historical because Hawaii does not currently observe daylight saving time.
Which cities use HST?
Cities in Hawaii that use HST include Honolulu, East Honolulu, Pearl City, Hilo, and Kailua. In practical terms, the entire state of Hawaii follows this time zone, which is why airlines, resorts, tour operators, and mainland businesses often use HST when confirming flights, check-ins, and meeting times.
What is the UTC offset for HST?
The exact UTC offset for HST is UTC−10:00. That means Hawaii is 10 hours behind UTC, so when it is 6:00 PM UTC, it is 8:00 AM HST on the same calendar day.
When does HST change?
Under current rules, HST does not change during the year. In 2026, there are no HST daylight saving transition dates, so clocks in Hawaii remain on UTC−10:00 from January through December.
Does Hawaii observe daylight saving time?
No, Hawaii does not observe daylight saving time today. This is why the time difference between Hawaii and mainland U.S. cities shifts in March and November when states like California and New York change their clocks, even though Hawaii stays fixed on HST.
How far behind New York is HST?
HST is 5 hours behind New York when New York is on Eastern Standard Time (UTC−5) and 6 hours behind when New York is on Eastern Daylight Time (UTC−4). For example, 9:00 AM in Honolulu corresponds to 2:00 PM in New York in winter and 3:00 PM in New York in summer, which matters for finance, media, and customer support scheduling.
Is HST the same as UTC-10?
HST uses the same numeric offset as UTC−10:00, but the terms are not always interchangeable in every context. UTC−10 is a pure offset, while HST is a regional time-zone label specifically associated with Hawaii; other places with the same offset may use abbreviations such as CKT or TAHT, so the location still matters.