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JST to MST converter
Japan Standard Time
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Mountain Time
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Mountain Time is 15 hours behind Japan Standard Time for most of the year, and 16 hours behind for part of it, because the two change their clocks on different dates (or only one of them changes at all).
When does the difference change?
In 2026:
- January 1 to March 7: Mountain Time is 16 hours behind Japan Standard Time
- March 8 to October 31: Mountain Time is 15 hours behind Japan Standard Time
- November 1 to December 31: Mountain Time is 16 hours behind Japan Standard Time
Questions
What time is 9 AM JST in MST?
For most of the year, 9 AM Japan Standard Time is 6 PM the day before Mountain Time. For part of the year it is 5 PM the day before, because of daylight saving time.
How many hours ahead or behind is MST from JST?
Mountain Time is 15 hours behind Japan Standard Time for most of the year, and 16 hours behind for part of it, because the two change their clocks on different dates (or only one of them changes at all).
Does the JST to MST difference change?
Yes. It changes 2 times in 2026 because of daylight saving time.
About these time zones
JST to MST, hour by hour
| Japan Standard Time | Mountain Time |
|---|---|
| 12 AM | 9 AM (previous day) |
| 1 AM | 10 AM (previous day) |
| 2 AM | 11 AM (previous day) |
| 3 AM | 12 PM (previous day) |
| 4 AM | 1 PM (previous day) |
| 5 AM | 2 PM (previous day) |
| 6 AM | 3 PM (previous day) |
| 7 AM | 4 PM (previous day) |
| 8 AM | 5 PM (previous day) |
| 9 AM | 6 PM (previous day) |
| 10 AM | 7 PM (previous day) |
| 11 AM | 8 PM (previous day) |
| 12 PM | 9 PM (previous day) |
| 1 PM | 10 PM (previous day) |
| 2 PM | 11 PM (previous day) |
| 3 PM | 12 AM |
| 4 PM | 1 AM |
| 5 PM | 2 AM |
| 6 PM | 3 AM |
| 7 PM | 4 AM |
| 8 PM | 5 AM |
| 9 PM | 6 AM |
| 10 PM | 7 AM |
| 11 PM | 8 AM |
Based on the clocks on Monday, October 12, 2026. Use the converter above for another date.