HST to MDT Converter & Meeting Planner
Quick answer: 9:00 AM HST = 1:00 PM MDT (fixed -10:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Hawaii-Aleutian Standard Time (HST) and Mountain Daylight Time (MDT)? You need to account for the standard time difference. Mountain Daylight Time is normally 4 hours ahead of Hawaii-Aleutian Standard Time. Whether you are coordinating between teams in Honolulu and Hilo and Denver and Salt Lake City, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM HST = 4:00 AM MDT. The full 24-hour HST to MDT table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM HST = 7:00 PM MDT.
| HST Time | MDT Time |
|---|---|
| 12:00 AM (00:00) | 4:00 AM (04:00) |
| 1:00 AM (01:00) | 5:00 AM (05:00) |
| 2:00 AM (02:00) | 6:00 AM (06:00) |
| 3:00 AM (03:00) | 7:00 AM (07:00) |
| 4:00 AM (04:00) | 8:00 AM (08:00) |
| 5:00 AM (05:00) | 9:00 AM (09:00) |
| 6:00 AM (06:00) | 10:00 AM (10:00) |
| 7:00 AM (07:00) | 11:00 AM (11:00) |
| 8:00 AM (08:00) | 12:00 PM (12:00) |
| 9:00 AM (09:00) | 1:00 PM (13:00) |
| 10:00 AM (10:00) | 2:00 PM (14:00) |
| 11:00 AM (11:00) | 3:00 PM (15:00) |
| 12:00 PM (12:00) | 4:00 PM (16:00) |
| 1:00 PM (13:00) | 5:00 PM (17:00) |
| 2:00 PM (14:00) | 6:00 PM (18:00) |
| 3:00 PM (15:00) | 7:00 PM (19:00) |
| 4:00 PM (16:00) | 8:00 PM (20:00) |
| 5:00 PM (17:00) | 9:00 PM (21:00) |
| 6:00 PM (18:00) | 10:00 PM (22:00) |
| 7:00 PM (19:00) | 11:00 PM (23:00) |
| 8:00 PM (20:00) | 12:00 AM (00:00)+1 day |
| 9:00 PM (21:00) | 1:00 AM (01:00)+1 day |
| 10:00 PM (22:00) | 2:00 AM (02:00)+1 day |
| 11:00 PM (23:00) | 3:00 AM (03:00)+1 day |
Best time to call Denver from Honolulu
For most work calls, compare the normal business day in Honolulu (HST) with the business day in Denver (MDT). HST commonly covers Pacific Ocean, North America, while MDT is mainly associated with North America.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
✅ The most practical overlap on 2026-07-05 is usually 9:00 AM - 1:00 PM HST, which corresponds to 1:00 PM - 5:00 PM MDT. This window sits inside the typical HST workday (9:00 AM - 5:00 PM) and the MDT workday (9:00 AM - 5:00 PM).
- DST Safety: HST or MDT may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
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Frequently Asked Questions
What is the time difference between HST and MDT?
During standard time, Mountain Daylight Time is 4 hours ahead of Hawaii-Aleutian Standard Time.
Does Hawaii observe Daylight Saving Time?
Hawaii does not observe Daylight Saving Time and has not done so since 1947, remaining fixed at UTC-10:00 year-round. At roughly 20° North latitude, Hawaii's daylight hours vary by only about 1.5 hours between the summer and winter solstices — far too little to justify the disruption of a seasonal clock change.
Why is it called Hawaii-Aleutian time?
The name combines two geographically distant US territories that share the same UTC-10:00 standard offset: the Hawaiian Islands in the central Pacific and the westernmost Aleutian Islands of Alaska, which extend past the 180° meridian into the Eastern Hemisphere. Despite sharing a base offset, they behave differently — Hawaii observes no DST, while the Aleutian communities such as Adak do advance to HDT (UTC-9) each summer.
When does MDT start and end?
MDT begins on the second Sunday in March at 02:00 local MST time, when clocks spring forward one hour from MST (UTC-7) to MDT (UTC-6). It ends on the first Sunday in November at 02:00 local MDT time, when clocks fall back to MST. In 2026, MDT runs from March 8 through November 1, covering the majority of the calendar year.
Is Arizona on MDT?
Most of Arizona — including Phoenix and Tucson — does not observe Daylight Saving Time and remains on MST (UTC-7) year-round under a state law in effect since 1968, meaning Arizona does not advance to MDT each March. The significant exception is the Navajo Nation, a sovereign territory spanning parts of northeastern Arizona, southeastern Utah, and northwestern New Mexico, which does observe DST and shifts to MDT on the standard federal schedule.