MDT to SST Converter
Convert time between Mountain Daylight Time (MDT) and Samoa Standard Time (SST)
Mountain Daylight Time (MDT)
Samoa Standard Time (SST)
Time Difference
Samoa Standard Time (SST) is 0 hours ahead of Mountain Daylight Time (MDT)
Select Date
Select Time
Quick Reference
| MDT | SST |
|---|---|
| 20:00 | 15:00 |
| 22:00 | 17:00 |
| 00:00 | 19:00 |
| 02:00 | 21:00 |
| 04:00 | 23:00 |
| 06:00 | 01:00 |
| 08:00 | 03:00 |
| 10:00 | 05:00 |
| 12:00 | 07:00 |
| 14:00 | 09:00 |
| 16:00 | 11:00 |
| 18:00 | 13:00 |
Top 10 Most Common Time Zones
| Abbreviation | Full Name | UTC Offset | Typical Use |
|---|---|---|---|
| UTC | Coordinated Universal Time | UTC ±0 | Global reference standard (servers, logs, APIs) |
| EST / EDT | Eastern (US) Time | UTC −5 / −4 | New York, Toronto — North American business hub |
| CST / CDT | Central (US) Time | UTC −6 / −5 | Chicago, Dallas — US central business region |
| PST / PDT | Pacific (US) Time | UTC −8 / −7 | San Francisco, Los Angeles — tech industry standard |
| GMT / BST | Greenwich Mean / British Summer Time | UTC 0 / +1 | UK, used globally as a reference with UTC |
| CET / CEST | Central European (Summer) Time | UTC +1 / +2 | Paris, Berlin, Amsterdam — EU business core |
| IST | India Standard Time | UTC +5:30 | India — major IT & outsourcing region |
| CST | China Standard Time | UTC +8 | Beijing, Shanghai — East Asia business hub |
| JST | Japan Standard Time | UTC +9 | Tokyo — finance & tech hub |
| AEST / AEDT | Australian Eastern (Daylight) Time | UTC +10 / +11 | Sydney, Melbourne — APAC regional business |
Why Time Zone Abbreviations Are Ambiguous
Unlike standardized identifiers (like America/New_York or Europe/London from the IANA tz database), abbreviations such as "CST" or "IST" are not globally unique. They can refer to different time zones depending on context — country, region, or even time of year (due to daylight saving time).
Common Ambiguous Time Zone Abbreviations
| Abbrev. | Common Meaning(s) | UTC Offset | Region(s) |
|---|---|---|---|
| CST | Central Standard Time / China Standard Time / Cuba Standard Time | UTC−6 / UTC+8 / UTC−5 | North America, China, Cuba |
| IST | Indian Standard Time / Irish Standard Time / Israel Standard Time | UTC+5:30 / UTC+1 / UTC+2 | India, Ireland, Israel |
| AST | Atlantic Standard Time / Arabia Standard Time | UTC−4 / UTC+3 | Caribbean, Canada, Middle East |
| PST | Pacific Standard Time / Philippine Standard Time | UTC−8 / UTC+8 | North America, Philippines |
| EST | Eastern Standard Time (North America / Australia) | UTC−5 / UTC+10 | North America, Australia |
✅ Best Practice
To avoid ambiguity, always:
- Use IANA tz identifiers — e.g.,
America/New_Yorkinstead of "EST" - Specify UTC offset explicitly — e.g.,
UTC−5when abbreviations must be used - Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset
About MDT to SST Time Conversion
Converting time between Mountain Daylight Time (MDT) and Samoa Standard Time (SST) bridges the US Mountain region and the South Pacific. MDT is UTC-6, while SST is UTC-11 and stays constant year-round (American Samoa does not observe daylight saving time). That makes SST 5 hours behind MDT during the US daylight saving period — from the second Sunday in March to the first Sunday in November. Outside that window the Mountain region (excluding Arizona) is on MST (UTC-7) and the gap shrinks to 4 hours.
This converter uses the IANA timezone database (America/Denver) to handle DST transitions automatically. Whether you're booking a call between Denver, Salt Lake City, or Calgary and Pago Pago during the summer months, or coordinating with Pacific-based teams across hemispheres, the tool removes the manual offset arithmetic. Note: most of Arizona stays on Mountain Standard Time year-round and does not switch to MDT.
Common Use Cases for MDT to SST Conversion
Business & Work
- Scheduling video calls between Denver, Salt Lake City, or Calgary and American Samoa in summer
- Coordinating US Mountain–Pacific remote team handoffs
- Planning conference calls that bridge Mountain and Samoan working hours
Personal & Travel
- Calling family in American Samoa from the Mountain US states or Alberta
- Planning flight connections via Los Angeles or Honolulu from Denver
- Coordinating watch parties for live NBA, NHL, or other US sports during American summer
Time Zone Information
Mountain Daylight Time (MDT)
- UTC Offset: UTC-6
- IANA Timezone: America/Denver
- Daylight Saving: Second Sunday in March to first Sunday in November (MDT)
- Major Cities: Denver, Phoenix (stays on MST), Salt Lake City, Albuquerque, Calgary
- Coverage: US Mountain time zone and Alberta during summer months. Most of Arizona stays on MST year-round.
Samoa Standard Time (SST)
- UTC Offset: UTC-11
- IANA Timezone: Pacific/Pago_Pago
- Daylight Saving: None - American Samoa does not observe daylight saving time
- Major Cities: Pago Pago, Tafuna, Nu'uuli, Faleniu, Aua
- Coverage: American Samoa and Midway Atoll
Quick Reference: MDT to SST
Remember: SST is 5 hours behind MDT. Outside US daylight saving (early November to mid-March) the Mountain region is on MST (UTC-7) and the gap is 4 hours. Most of Arizona stays on MST year-round.
Frequently Asked Questions
What is the time difference between MDT and SST?
Mountain Daylight Time (MDT) is UTC-6, while Samoa Standard Time (SST) is UTC-11. SST is 5 hours behind MDT. When it is 12:00 PM in Denver, it is 7:00 AM in Pago Pago.
When does this MDT to SST conversion apply?
It applies during US daylight saving, from the second Sunday in March to the first Sunday in November. Outside that window the Mountain region (excluding Arizona) is on MST (UTC-7) and the gap drops to 4 hours. American Samoa stays on SST (UTC-11) year-round.
How does the time difference change throughout the year?
The gap is 5 hours during MDT (mid-March to early November) and 4 hours during MST (early November to mid-March). American Samoa never observes daylight saving, so any seasonal change comes from the US side. Most of Arizona stays on MST year-round and does not switch to MDT.
What are the best times for MDT–SST business calls?
A 5-hour gap leaves a comfortable afternoon overlap: 2:00 PM MDT is 9:00 AM SST. Late-morning Pago Pago and early-afternoon Denver is the most usable live-call window.
Which countries and regions use SST?
Samoa Standard Time (UTC-11) is used in American Samoa and the uninhabited Midway Atoll. The independent state of Samoa is on UTC+13, on the opposite side of the international date line. Major American Samoa locations include Pago Pago, Tafuna, and Nu’uuli.
Which countries and regions use MDT?
Mountain Daylight Time applies in the US Mountain time zone and Alberta, Canada during summer — Colorado, Wyoming, Montana, Utah, New Mexico, and parts of neighboring states. Major cities include Denver, Salt Lake City, Albuquerque, and Calgary. Most of Arizona stays on MST year-round and does not switch to MDT.
Pro Tips
- • SST is 5 hours behind MDT — both sides share the same calendar day.
- • American Samoa never observes daylight saving, so any seasonal shift comes from the US side switching between MDT and MST.
- • Outside US daylight saving (early November to mid-March) the Mountain region is on MST (UTC-7) and the gap drops to 4 hours.
- • Most of Arizona stays on MST year-round — when you mean Phoenix, the gap is 4 hours regardless of season.
- • Early afternoon MDT and morning SST is the most workable overlap window for live calls.
- • For one-off calls, double-check the IANA zones (America/Denver, Pacific/Pago_Pago) in your calendar tool.