US Mountain Time to Canada Atlantic Time
Convert times between US Mountain Time (MST, UTC-7:00) and Canada Atlantic Time (AST, UTC-4:00). Canada Atlantic Time is 3 hours ahead of US Mountain Time in standard time.
UTC-7:00 / -6:00→UTC-4:00 / -3:00
Live timezone converterUTC Offset Reference
| Timezone | Abbreviation | Standard offset | DST offset | Country |
|---|---|---|---|---|
| US Mountain Time | MST / MDT | UTC-7:00 | UTC-6:00 | United States |
| Canada Atlantic Time | AST / ADT | UTC-4:00 | UTC-3:00 | Canada |
* DST offset applies during summer months. Exact transition dates vary by year.
Standard Time Conversion (MST → AST)
| US Mountain Time | Canada Atlantic Time |
|---|---|
| 12:00 AM MST | 3:00 AM AST |
| 6:00 AM MST | 9:00 AM AST |
| 9:00 AM MST | 12:00 PM AST |
| 12:00 PM MST | 3:00 PM AST |
| 3:00 PM MST | 6:00 PM AST |
| 6:00 PM MST | 9:00 PM AST |
| 9:00 PM MST | 12:00 AM (next day) AST |
Daylight Saving Time (DST) Notes
- US Mountain Time observes DST. Clocks advance 1 hour to MDT (UTC-6:00) roughly from month 3 to 11.
- Canada Atlantic Time observes DST. Clocks advance 1 hour to ADT (UTC-3:00) roughly from month 3 to 11.
Frequently Asked Questions
How do I convert MST to AST?
Add 3 hours to the MST time to get AST. For example, 9:00 AM MST = 12:00 PM AST.
What is the current UTC offset for US Mountain Time?
US Mountain Time is UTC-7:00 during standard time (MST) and UTC-6:00 during summer daylight saving time (MDT).
Is Canada Atlantic Time ahead or behind US Mountain Time?
Canada Atlantic Time is 3 hours ahead of US Mountain Time in standard time.
When is a good time to schedule a meeting between MST and AST?
A good overlap window is around 9:00 AM MST / 12:00 PM AST, which falls within business hours for both timezones.
Related Timezone Conversions
US Mountain Time → US Eastern TimeMST / ESTUS Mountain Time → US Central TimeMST / CSTUS Mountain Time → US Pacific TimeMST / PSTUS Mountain Time → US Alaska TimeMST / AKSTUS Mountain Time → Hawaii TimeMST / HSTUS Mountain Time → Greenwich Mean TimeMST / GMTUS Mountain Time → India Standard TimeMST / ISTUS Mountain Time → China Standard TimeMST / CST
Need the exact current time?
Use the live ToolsHub timezone converter to see current times, DST status, and schedule across time zones.