JST to Denver
-15hJST
JSTSOURCEDenver
MDTGreen rows indicate typical business hours (9 AM - 5 PM)
JST and MDT on the World Map
The map below highlights the JST (Japan Standard Time) and MDT (Mountain Standard Time) timezone regions across the globe.
JST – Japan Standard Time
UTC+09:00Japan Standard Time (JST) is the time zone for Japan, 9 hours ahead of UTC.
- •Japan does not observe daylight saving time.
- •Tokyo is the most populous metropolitan area in the world.
- •The Tokyo Stock Exchange operates from 9:00 AM to 3:00 PM JST.
- •JST is 14 hours ahead of EST and 9 hours ahead of GMT.
MST – Mountain Standard Time
UTC-07:00Mountain Standard Time (MST) is the time zone for the Mountain region of North America, 7 hours behind UTC.
- •Arizona does not observe daylight saving time, staying on MST year-round.
- •The Navajo Nation in Arizona does observe DST, unlike the rest of the state.
- •Denver, the 'Mile High City', is the largest city fully in MST.
- •MST covers 6 US states entirely and parts of several others.
About Denver
WikipediaDenver operates on Mountain Time (MST/MDT), 2 hours behind New York. As a tech and aerospace hub, Denver bridges West Coast and Central US business hours.
Denver International Airport is the largest airport in North America by land area.
JST to Denver Time Difference – Complete Guide
JST runs on Japan Standard Time (JST) at UTC+09:00. Denver runs on Mountain Daylight Time (MDT) at UTC-06:00, also currently on daylight saving time. That puts JST 15 hours behind Denver — a difference of -15h at the current offsets.
In practice, when it is 9:00 AM in JST it is 6:00 PM in Denver on the previous day. Midnight in JST is 9:00 AM in Denver.Denver observes daylight saving time while JST does not, so the gap narrows or widens by an hour part of the year.
JST to Denver time conversion table
| JST (JST) | Denver (MDT) | Day |
|---|---|---|
| 12:00 AM | 9:00 AM | previous day |
| 6:00 AM | 3:00 PM | previous day |
| 7:00 AM | 4:00 PM | previous day |
| 8:00 AM | 5:00 PM | previous day |
| 9:00 AM | 6:00 PM | previous day |
| 12:00 PM | 9:00 PM | previous day |
| 3:00 PM | 12:00 AM | same day |
| 5:00 PM | 2:00 AM | same day |
| 6:00 PM | 3:00 AM | same day |
| 9:00 PM | 6:00 AM | same day |
Why people convert JST to Denver time
- Scheduling a call from JST to Denver: a 10:00 AM start in JST lands at 7:00 PM in Denver the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -15h gap: JST and Denver have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in Denver is 6:00 PM in JST.
- Coordinating a JST-based team with Denver contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM JST" is unambiguous; "3 PM" across a -15h gap is not.
- With a -15h gap there is no shared 9-to-5 window, so alternate the early start: one week JST takes the early slot, the next week Denver does.
- Denver: Clocks fall back on Sun, Nov 1, 2026. Any meeting series spanning that date will shift by an hour in local time.
About JST (Japan Standard Time)
Japan Standard Time (JST) is the standard time zone for all of Japan. Japan does not observe daylight saving time. JST is 9 hours ahead of UTC and 14 hours ahead of EST. The Tokyo Stock Exchange, the world's third largest by market capitalization, operates on JST. South Korea uses the same offset (KST) but it is a distinct time zone.
About MST (Mountain Standard Time)
Mountain Standard Time (MST) covers the Rocky Mountain region of the United States and Canada. Arizona is notable for not observing daylight saving time, staying on MST year-round (except the Navajo Nation). The time zone includes major cities like Denver, Phoenix, Calgary, and Salt Lake City. During summer, most areas switch to Mountain Daylight Time (MDT, UTC-06:00).
Best time to call between JST and Denver
With a -15h offset there is no overlap inside a normal 9 AM – 5 PM day. Denver opens at 9:00 AM MDT, which is 6:00 PM in JST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
JST and Denver have no shared working hours because of the -15h gap. Teams need to alternate early starts or rely on asynchronous handovers.
JST is 15 hours behind Denver (JST UTC+09:00 → MDT UTC-06:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
JST
Does not observe DST
Denver
☀ Currently in DST
Standard: UTC-07:00 · DST: UTC-06:00
Clocks fall back on Sun, Nov 1, 2026
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between JST and Denver?
JST (JST, UTC+09:00) is 15 hours behind Denver (MDT, UTC-06:00). The gap is currently -15h.
How do I convert JST time to Denver time?
Add -15h to JST local time. For example, 9:00 AM in JST is 6:00 PM in Denver (previous day).
What time is it in Denver right now?
Denver uses MDT at UTC-06:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -15h offset from JST.
What is the best time to call Denver from JST?
There is no shared working-hours window because of the -15h gap. The closest option is 1:00 PM in JST, which is 10:00 PM in Denver.
Which is behind, JST or Denver?
JST is 15 hours behind Denver. When it is 12:00 PM in JST it is 9:00 PM in Denver.
Do JST and Denver use different time zones?
JST uses JST at UTC+09:00, while Denver (USA) uses MDT at UTC-06:00. The IANA identifiers are Asia/Tokyo and America/Denver.
Does daylight saving time affect the JST–Denver difference?
Yes at the moment: Denver is on daylight saving time and JST is not, so the -15h gap shifts by an hour when exactly one of them changes clocks.
Which other cities share JST's time zone?
JST also covers Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka and 1 more.
Which countries use JST, JST's zone?
JST is used in Japan.
Is there a day difference between JST and Denver?
Sometimes. The -15h gap is large enough that 8:00 PM or later in JST already falls on the in Denver.
What is the time difference between JST and Denver?
Denver is -15h from JST.
What timezone is JST in?
JST operates on its local timezone.
What timezone is Denver in?
Denver operates on Mountain Time (MST/MDT), 2 hours behind New York. As a tech and aerospace hub, Denver bridges West Coast and Central US business hours.
What are the business hours in Denver?
Standard business hours in Denver are 8:00 AM - 5:00 PM MST.
Which countries use JST (Japan Standard Time)?
JST is used in Japan.
Does JST observe daylight saving time?
No, JST does not observe daylight saving time and remains at UTC+09:00 year-round.
What are some interesting facts about JST?
Japan does not observe daylight saving time. Tokyo is the most populous metropolitan area in the world.
Which cities are in the MST timezone?
Major cities in the MST timezone include Denver, Phoenix, Salt Lake City, Calgary, Edmonton, Albuquerque, El Paso, Tucson.
What is the UTC offset for MST?
Mountain Standard Time (MST) is at UTC-07:00. During daylight saving time, it shifts to MDT.
What should I know about the MST timezone?
Arizona does not observe daylight saving time, staying on MST year-round. The Navajo Nation in Arizona does observe DST, unlike the rest of the state.
When is it midnight in JST, what time is it in Denver?
When it is 12:00 AM (midnight) in JST (JST), it is -15h later in Denver (MST).
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