MST to AWST Converter
Convert time between Mountain Standard Time (MST) and Australian Western Standard Time (AWST)
Mountain Standard Time (MST)
Australian Western Standard Time (AWST)
Time Difference
Australian Western Standard Time (AWST) is 0 hours ahead of Mountain Standard Time (MST)
Select Date
Select Time
Quick Reference
| MST | AWST |
|---|---|
| 20:00 | 10:00 |
| 22:00 | 12:00 |
| 00:00 | 14:00 |
| 02:00 | 16:00 |
| 04:00 | 18:00 |
| 06:00 | 20:00 |
| 08:00 | 22:00 |
| 10:00 | 00:00 |
| 12:00 | 02:00 |
| 14:00 | 04:00 |
| 16:00 | 06:00 |
| 18:00 | 08:00 |
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 MST to AWST Time Conversion
Converting time between Mountain Standard Time (MST) and Australian Western Standard Time (AWST) spans a 15-hour difference. MST is UTC-7 (observed during winter in the US Mountain region), while AWST is UTC+8, making Perth 15 hours ahead of Denver. When it is noon in Denver on MST, it is already 3:00 AM the next day in Perth.
This time zone converter uses the IANA timezone database for accurate calculations. MST applies from the first Sunday in November to the second Sunday in March across most of the US Mountain region, when clocks fall back from MDT. AWST does not observe daylight saving time and stays at UTC+8 year-round. During US summer, the Mountain region shifts to MDT (UTC-6), reducing the gap to 14 hours.
Common Use Cases for MST to AWST Conversion
Business & Work
- Scheduling video calls between Mountain region offices and Perth-based teams during US winter
- Coordinating project handoffs across the US Mountain and Western Australia time zones
- Planning webinars and virtual events for participants in both Denver and Perth
Personal & Travel
- Staying connected with family and friends between the Mountain states and Perth
- Planning Pacific travel itineraries across multiple time zones
- Scheduling online events with participants in both the US Mountain region and Western Australia
Time Zone Information
Mountain Standard Time (MST)
- UTC Offset: UTC-7
- IANA Timezone: America/Denver
- Daylight Saving: First Sunday in November to Second Sunday in March (winter season)
- Major Cities: Denver, Salt Lake City, Albuquerque, Boise, Phoenix
- Coverage: US Mountain states including Colorado, Utah, New Mexico, Idaho, and Arizona (year-round for AZ)
Australian Western Standard Time (AWST)
- UTC Offset: UTC+8
- IANA Timezone: Australia/Perth
- Daylight Saving: Western Australia does not observe daylight saving time
- Major Cities: Perth, Fremantle, Mandurah, Bunbury, Geraldton
- Coverage: Western Australia, Australia's largest state by area
Quick Reference: MST to AWST
Remember: AWST is always 15 hours ahead of MST during US Mountain Standard Time
Frequently Asked Questions
What is the time difference between MST and AWST?
Mountain Standard Time (MST) is UTC-7, while Australian Western Standard Time (AWST) is UTC+8. AWST is 15 hours ahead of MST. When it's 12:00 PM in Denver on MST, it's 3:00 AM the next day in Perth.
When does MST apply?
Mountain Standard Time (MST) is observed in the US Mountain region from the first Sunday in November to the second Sunday in March — the winter months. During the rest of the year, most of the Mountain region observes MDT (UTC-6), which is 14 hours behind AWST. Arizona (except the Navajo Nation) uses MST year-round.
Does Western Australia observe daylight saving time?
No. Western Australia does not observe daylight saving time. AWST remains at UTC+8 year-round. When the US Mountain region shifts from MST (UTC-7) to MDT (UTC-6) in March, the offset between the two zones decreases from 15 to 14 hours.
What are the best times to schedule calls between MST and AWST?
The scheduling overlap is difficult. Late afternoon in Perth (4:00–6:00 PM AWST) corresponds to 1:00–3:00 AM MST the previous day. Early morning in Denver (7:00–9:00 AM MST) maps to 10:00 PM–12:00 AM AWST. The most workable window is evening in Denver (5:00–8:00 PM MST), which lands at 8:00–11:00 AM AWST in Perth.
Which US states observe Mountain Standard Time year-round?
Arizona (except the Navajo Nation) observes MST year-round and never switches to MDT. Other Mountain states — Colorado, Utah, New Mexico, Idaho, Wyoming, and Montana — observe MST only in winter (November to March), switching to MDT in summer.
Which cities are in the AWST timezone?
AWST covers all of Western Australia. Perth is the largest city and a major hub for mining and energy industries. Other significant cities include Fremantle, Mandurah, Bunbury, and Geraldton. Western Australia operates on AWST year-round with no seasonal clock change.
Pro Tips
- • AWST is 15 hours ahead of MST — add 15 hours (and advance the date by one day) to convert Mountain Standard Time to Perth time.
- • In summer (March–November), Mountain clocks shift to MDT (UTC-6), reducing the gap to 14 hours — check which season applies before converting.
- • Arizona uses MST year-round, so Phoenix never shifts to MDT — the MST-to-AWST gap stays at 15 hours for Arizona contacts regardless of season.
- • The sweet spot for scheduling is Denver evening (5–8 PM MST), which lands at Perth morning (8–11 AM AWST).
- • Denver and Perth are separated by roughly 14,500 km across the Pacific — always double-check the calendar date when sharing a meeting time.
- • Use a world clock tool pinned to both MST and AWST to avoid manually calculating the date rollover.