What is ART in MST?
Mountain Time is 3 hours behind
Argentina Time is on UTC−3:00 and Mountain Time is on UTC−6:00 right now. Mountain Time is on daylight saving, so its clocks read MDT. The gap changes during the year — see below.
- Time in Buenos Aires
- 11:14 pm
- Time in Denver
- 8:14 pm
- Difference
- −3 h
- Next clock change
- November 1, 2026
Convert a time
MDT — Mountain Time
8:00 pm
Tue
When the difference changes
Argentina Time and Mountain Time do not change their clocks on the same dates, so the gap between them is not the same all year. Most converters show only today’s figure. These are the periods ahead:
- Now – November 1, 2026Mountain Time is 3 hours behind
- November 1, 2026 – March 14, 2027Mountain Time is 4 hours behind
- March 14, 2027 – onwardsMountain Time is 3 hours behind
Periods shorter than a day are not listed: both zones change at 2am in their own local time, so there are a few hours on each transition date when the gap is briefly something else.
Daylight saving
Argentina Time
Argentina Time stays on ART all year, so its offset from UTC never moves.
Mountain Time
Clocks go back one hour at 2am local time, becoming MST.
ART to MST conversion table
Every hour of Tuesday, September 22, 2026, converted from Argentina Time to Mountain Time. 3 of the 24 hours fall on a different calendar day in Denver, which is marked.
- 12:00 am ART
- 9:00 pm MDT−1 day
- 1:00 am ART
- 10:00 pm MDT−1 day
- 2:00 am ART
- 11:00 pm MDT−1 day
- 3:00 am ART
- 12:00 am MDT
- 4:00 am ART
- 1:00 am MDT
- 5:00 am ART
- 2:00 am MDT
- 6:00 am ART
- 3:00 am MDT
- 7:00 am ART
- 4:00 am MDT
- 8:00 am ART
- 5:00 am MDT
- 9:00 am ART
- 6:00 am MDT
- 10:00 am ART
- 7:00 am MDT
- 11:00 am ART
- 8:00 am MDT
- 12:00 pm ART
- 9:00 am MDT
- 1:00 pm ART
- 10:00 am MDT
- 2:00 pm ART
- 11:00 am MDT
- 3:00 pm ART
- 12:00 pm MDT
- 4:00 pm ART
- 1:00 pm MDT
- 5:00 pm ART
- 2:00 pm MDT
- 6:00 pm ART
- 3:00 pm MDT
- 7:00 pm ART
- 4:00 pm MDT
- 8:00 pm ART
- 5:00 pm MDT
- 9:00 pm ART
- 6:00 pm MDT
- 10:00 pm ART
- 7:00 pm MDT
- 11:00 pm ART
- 8:00 pm MDT
Scheduling between the two
Working hours overlap from 12:00 pm to 6:00 pm ART, which is 9:00 am to 3:00 pm MDT. Anything inside that window falls in the normal working day at both ends.
Mountain Time (MDT) is used in Salt Lake City, Albuquerque and Calgary. Arizona keeps MST all year and does not follow MDT.