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DateAlmanac

What is JST in MST?

Mountain Time is 16 hours behind

Japan Standard Time is on UTC+9:00 and Mountain Time is on UTC−7:00 right now. The gap changes during the year — see below.

Convert a time

MST — Mountain Time

1:00 am

MST, Sat

Time in Tokyo
5:29:37 PM
Time in Denver
1:29:37 AM
Difference
−16 h
Next clock change
March 14, 2027

When the difference changes

Japan Standard 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:

  1. Now – March 14, 2027Mountain Time is 16 hours behind
  2. March 14, 2027 – November 7, 2027Mountain Time is 15 hours behind
  3. November 7, 2027 – onwardsMountain Time is 16 hours behind

Periods shorter than a day are not listed. Each zone changes at its own local time, so on a date when both move there are a few hours when the gap is briefly something else.

Daylight saving

Japan Standard Time

No clock changes

Japan Standard Time stays on JST all year, so its offset from UTC never moves.

Mountain Time

Sunday, March 14, 2027

Clocks go forward one hour — 2:00 am becomes 3:00 am local time, and the zone is on MDT after that.

JST to MST conversion table

Every hour of Saturday, November 7, 2026, converted from Japan Standard Time to Mountain Time. 16 of the 24 hours fall on a different calendar day in Denver, which is marked.

12:00 am JST
8:00 am MST−1 day
1:00 am JST
9:00 am MST−1 day
2:00 am JST
10:00 am MST−1 day
3:00 am JST
11:00 am MST−1 day
4:00 am JST
12:00 pm MST−1 day
5:00 am JST
1:00 pm MST−1 day
6:00 am JST
2:00 pm MST−1 day
7:00 am JST
3:00 pm MST−1 day
8:00 am JST
4:00 pm MST−1 day
9:00 am JST
5:00 pm MST−1 day
10:00 am JST
6:00 pm MST−1 day
11:00 am JST
7:00 pm MST−1 day
12:00 pm JST
8:00 pm MST−1 day
1:00 pm JST
9:00 pm MST−1 day
2:00 pm JST
10:00 pm MST−1 day
3:00 pm JST
11:00 pm MST−1 day
4:00 pm JST
12:00 am MST
5:00 pm JST
1:00 am MST
6:00 pm JST
2:00 am MST
7:00 pm JST
3:00 am MST
8:00 pm JST
4:00 am MST
9:00 pm JST
5:00 am MST
10:00 pm JST
6:00 am MST
11:00 pm JST
7:00 am MST

Scheduling between the two

Working hours overlap from 9:00 am to 10:00 am JST, which is 5:00 pm to 6:00 pm MST. Anything inside that window falls in the normal working day at both ends.

Mountain Time (MST) is used in Salt Lake City, Albuquerque and Calgary. Arizona keeps MST all year and does not follow MDT.

Other conversions