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Canada Atlantic Time to US Mountain Time

Convert times between Canada Atlantic Time (AST, UTC-4:00) and US Mountain Time (MST, UTC-7:00). US Mountain Time is 3 hours behind Canada Atlantic Time in standard time.

UTC-4:00 / -3:00UTC-7:00 / -6:00
Live timezone converter

UTC Offset Reference

TimezoneAbbreviationStandard offsetDST offsetCountry
Canada Atlantic TimeAST / ADTUTC-4:00UTC-3:00Canada
US Mountain TimeMST / MDTUTC-7:00UTC-6:00United States

* DST offset applies during summer months. Exact transition dates vary by year.

Standard Time Conversion (ASTMST)

Canada Atlantic TimeUS Mountain Time
12:00 AM AST9:00 PM (prev day) MST
6:00 AM AST3:00 AM MST
9:00 AM AST6:00 AM MST
12:00 PM AST9:00 AM MST
3:00 PM AST12:00 PM MST
6:00 PM AST3:00 PM MST
9:00 PM AST6:00 PM MST

Daylight Saving Time (DST) Notes

  • Canada Atlantic Time observes DST. Clocks advance 1 hour to ADT (UTC-3:00) roughly from month 3 to 11.
  • US Mountain Time observes DST. Clocks advance 1 hour to MDT (UTC-6:00) roughly from month 3 to 11.

Frequently Asked Questions

How do I convert AST to MST?
Add (-3) hours to the AST time to get MST. For example, 9:00 AM AST = 6:00 AM MST.
What is the current UTC offset for Canada Atlantic Time?
Canada Atlantic Time is UTC-4:00 during standard time (AST) and UTC-3:00 during summer daylight saving time (ADT).
Is US Mountain Time ahead or behind Canada Atlantic Time?
US Mountain Time is 3 hours behind Canada Atlantic Time in standard time.
When is a good time to schedule a meeting between AST and MST?
A good overlap window is around 12:00 PM AST / 9:00 AM MST, which falls within business hours for both timezones.

Need the exact current time?

Use the live ToolsHub timezone converter to see current times, DST status, and schedule across time zones.

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