MDT to HST
-4hMDT
MDTSOURCEHST
HSTGreen rows indicate typical business hours (9 AM - 5 PM)
MDT and HST on the World Map
The map below highlights the MDT (Mountain Daylight Time) and HST (Hawaii Standard Time) timezone regions across the globe.
MDT – Mountain Daylight Time
UTC-06:00Mountain Daylight Time (MDT) is the daylight saving offset in the Mountain Time Zone, 6 hours behind UTC.
- •MDT shares the same offset as CST (UTC-06:00).
- •Arizona does not switch to MDT, remaining on MST.
HST – Hawaii Standard Time
UTC-10:00Hawaii Standard Time (HST) is the time zone for the Hawaiian Islands, 10 hours behind UTC.
- •Hawaii does not observe daylight saving time.
- •HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
- •Hawaii is one of only two US states that don't observe DST (the other is Arizona).
Understanding the -4h Gap: MDT vs HST
MDT runs on Mountain Daylight Time (MDT) at UTC-06:00. HST runs on Hawaii Standard Time (HST) at UTC-10:00. That puts MDT 4 hours behind HST — a difference of -4h at the current offsets.
In practice, when it is 9:00 AM in MDT it is 5:00 AM in HST. Midnight in MDT is 8:00 PM in HST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
MDT to HST time conversion table
| MDT (MDT) | HST (HST) | Day |
|---|---|---|
| 12:00 AM | 8:00 PM | previous day |
| 6:00 AM | 2:00 AM | same day |
| 7:00 AM | 3:00 AM | same day |
| 8:00 AM | 4:00 AM | same day |
| 9:00 AM | 5:00 AM | same day |
| 12:00 PM | 8:00 AM | same day |
| 3:00 PM | 11:00 AM | same day |
| 5:00 PM | 1:00 PM | same day |
| 6:00 PM | 2:00 PM | same day |
| 9:00 PM | 5:00 PM | same day |
Why people convert MDT to HST time
- Scheduling a call from MDT to HST: a 10:00 AM start in MDT lands at 6:00 AM in HST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both MDT and HST are inside the 9-to-5 working day between 1:00 PM and 5:00 PM MDT time (9:00 AM–1:00 PM HST). That is roughly 4 hours of usable overlap.
- Coordinating a MDT-based team with HST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM MDT" is unambiguous; "3 PM" across a -4h gap is not.
- Block 1:00 PM–5:00 PM MDT as the recurring meeting window if you work primarily from MDT and need HST colleagues present.
About MDT (Mountain Daylight Time)
Mountain Daylight Time (MDT) is observed during summer months in the Mountain Time Zone, except in Arizona which stays on MST year-round. MDT aligns with Central Standard Time (CST) at UTC-06:00.
About HST (Hawaii Standard Time)
Hawaii Standard Time (HST) is used in the state of Hawaii and does not observe daylight saving time. This makes HST one of the most consistent time zones in the US. The Hawaiian Islands are among the last places on Earth to see a new calendar day.
Best time to call between MDT and HST
Both MDT and HST sit inside the 9 AM – 5 PM working day between 1:00 PM–5:00 PM MDT, which is 9:00 AM–1:00 PM HST. That gives roughly 4 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
MDT and HST overlap for about 4 hours during the working day — enough for meetings if you avoid the edges of the window.
MDT is 4 hours behind HST (MDT UTC-06:00 → HST UTC-10:00). The shared working window is 1:00 PM–5:00 PM MDT. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
MDT
☀ Currently in DST
Standard: UTC-07:00 · DST: UTC-06:00
Clocks fall back on Sun, Nov 1, 2026
HST
Does not observe DST
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between MDT and HST?
MDT (MDT, UTC-06:00) is 4 hours behind HST (HST, UTC-10:00). The gap is currently -4h.
How do I convert MDT time to HST time?
Add -4h to MDT local time. For example, 9:00 AM in MDT is 5:00 AM in HST.
What time is it in HST right now?
HST uses HST at UTC-10:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -4h offset from MDT.
What is the best time to call HST from MDT?
Call between 1:00 PM and 5:00 PM MDT — that maps to 9:00 AM–1:00 PM HST and keeps both parties inside the working day.
Which is behind, MDT or HST?
MDT is 4 hours behind HST. When it is 12:00 PM in MDT it is 8:00 AM in HST.
Does daylight saving time affect the MDT–HST difference?
Neither zone observes daylight saving time, so the -4h offset between MDT and HST is fixed all year.
Which other cities share MDT's time zone?
MDT also covers Denver, Calgary, Edmonton, Salt Lake City, Boise.
Which countries use MDT, MDT's zone?
MDT is used in United States (Mountain), Canada (Alberta).
Is there a day difference between MDT and HST?
Not normally. The -4h gap only pushes the date over the previous day.
What is the time difference between MDT and HST?
HST is -4h from MDT.
What timezone is MDT in?
MDT operates on its local timezone.
What timezone is HST in?
HST operates on its local timezone.
Which countries use MDT (Mountain Daylight Time)?
MDT is used in United States (Mountain), Canada (Alberta).
Does MDT observe daylight saving time?
Yes, MDT switches to MST during summer months.
What are some interesting facts about MDT?
MDT shares the same offset as CST (UTC-06:00). Arizona does not switch to MDT, remaining on MST.
Which cities are in the HST timezone?
Major cities in the HST timezone include Honolulu, Hilo, Kailua, Pearl City, Kapolei.
What is the UTC offset for HST?
Hawaii Standard Time (HST) is at UTC-10:00.
What should I know about the HST timezone?
Hawaii does not observe daylight saving time. HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
When is it midnight in MDT, what time is it in HST?
When it is 12:00 AM (midnight) in MDT (MDT), it is -4h later in HST (HST).
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See every conversion from MDT →·See every conversion from HST →