ART to MT Time Converter
MT is 3 hours behind ART. ART is UTC-3:00, and The US Mountain states are currently on MDT (UTC-6:00).
Best Time to Call Between ART and MT
Both zones are inside normal business hours between 12:00 PM and 5:00 PM ART — that's 9:00 AM to 2:00 PM MT. That's a 5-hour window.
both at work ART only MT only neither — hours along the strip are ART.
Common Times Converted
ART on the left, MT on the right.
ART to MT: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| ART | MT | Working hours |
|---|---|---|
| 12:00 AM | 9:00 PM prev day | — |
| 1:00 AM | 10:00 PM prev day | — |
| 2:00 AM | 11:00 PM prev day | — |
| 3:00 AM | 12:00 AM | — |
| 4:00 AM | 1:00 AM | — |
| 5:00 AM | 2:00 AM | — |
| 6:00 AM | 3:00 AM | — |
| 7:00 AM | 4:00 AM | — |
| 8:00 AM | 5:00 AM | — |
| 9:00 AM | 6:00 AM | ART only |
| 10:00 AM | 7:00 AM | ART only |
| 11:00 AM | 8:00 AM | ART only |
| 12:00 PM | 9:00 AM | Both zones |
| 1:00 PM | 10:00 AM | Both zones |
| 2:00 PM | 11:00 AM | Both zones |
| 3:00 PM | 12:00 PM | Both zones |
| 4:00 PM | 1:00 PM | Both zones |
| 5:00 PM | 2:00 PM | MT only |
| 6:00 PM | 3:00 PM | MT only |
| 7:00 PM | 4:00 PM | MT only |
| 8:00 PM | 5:00 PM | — |
| 9:00 PM | 6:00 PM | — |
| 10:00 PM | 7:00 PM | — |
| 11:00 PM | 8:00 PM | — |
What ART and MT Actually Are
ART — Argentina Time
Buenos Aires, Córdoba, Rosario. Standing at UTC-3:00 as written, and the region does not change its clocks, so that offset holds all year. Argentina does not observe daylight saving, so this offset is fixed year-round.
Argentina has changed its time zone rules more than a dozen times since 1930 and abandoned daylight saving in 2009.
MT — Mountain Time
Denver, Salt Lake City, Calgary, Edmonton — and Phoenix, which does not change its clocks. Standing at UTC-7:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to MST.
Mountain Time contains the most conspicuous daylight saving exception in North America: Arizona, which has opted out since 1968.
What This Means in Practice
This gap is not fixed
MT changes its clocks and ART does not, so the difference between them moves by an hour twice a year. A recurring meeting set now will drift for one side from Sunday, November 1, 2026 unless someone resets it.
Major Cities in Each Zone
Cities on ART
Cities on MT
Frequently Asked Questions
What is the time difference between ART and MT?
MT is 3 hours behind ART. That is the live figure. Taken strictly as written, the gap between ART and MT is 4 hours — the two differ because at least one of these regions is currently on daylight saving.
What is 9:00 AM ART in MT?
9:00 AM ART is 6:00 AM MT.
What are the best hours to schedule a call between ART and MT?
Between 12:00 PM and 5:00 PM ART, which is 9:00 AM to 2:00 PM MT. Both sides are inside normal business hours through that window.
Does the difference between ART and MT change during the year?
Yes. MT observes daylight saving and ART does not, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, November 1, 2026.
Does ART always mean Argentina Time?
Argentina does not observe daylight saving, so this offset is fixed year-round.