Denver uses US Mountain Time, but “Mountain Time” does not have a fixed UTC offset throughout the year. The same morning in Taipei may correspond to the previous evening in Denver, or to an hour earlier on that previous day. When planning an airport pickup, hotel check-in, or a call with a local friend, the easiest mistake is to remember the time difference from one trip without checking the dates for this trip again.
You can work out Denver time in three steps: first identify whether standard time or daylight saving time applies, then convert the date between Taipei and Denver, and finally save the appointment in the correct city time zone. This article sets out a method that works all year, rather than treating the clock at one particular moment as a permanent answer. To see the city’s current time, open the CityTimeDate Denver city page, then use this method to check your travel date.
Denver Mountain Time has two UTC offsets
Denver uses MST, or UTC−07:00, during standard time. When daylight saving time is in effect, it uses MDT, or UTC−06:00. MT usually refers to Mountain Time in general; you need the date to know which offset applies. When confirming an appointment, do not ask only “Is it nine Mountain time?” Also confirm the event date and whether the organizer means local Denver time or fixed MST. IANA’s time zone theory uses America/Denver as an example of a Mountain time zone that follows US daylight saving rules.
Under current US rules, daylight saving time begins at 2 a.m. local time on the second Sunday in March, when clocks jump directly to 3 a.m. It ends at 2 a.m. local time on the first Sunday in November, when clocks return to 1 a.m. Thus one change creates a period of time that does not exist, while the other repeats a period of time. Typical daytime plans are less likely to encounter this, but check carefully for early-morning arrivals, nighttime pickups, or lodging handoffs. NIST’s daylight saving time rules explain the current changeover principles; for future plans, use the rules that apply to the date you are checking.
Converting Taipei and Denver: check the hour, then the date
Taipei uses UTC+08:00. During Denver standard time, Taipei is 15 hours ahead of Denver; during Denver daylight saving time, Taipei is 14 hours ahead. To convert Taipei time to Denver time, subtract the corresponding number of hours. To convert Denver time to Taipei time, add that number. If the calculation crosses midnight, move the date back or forward by one day too; do not change only the clock number.
For example, 9 a.m. Tuesday in Taipei corresponds to 6 p.m. Monday in Denver during standard time, and 7 p.m. Monday during daylight saving time. In the other direction, 9 a.m. Monday in Denver corresponds to midnight Tuesday in Taipei during standard time, and 11 p.m. Monday in Taipei during daylight saving time. These examples show that a one-hour difference can also change the date.
In practice, write the full date and time for both places on the same line, then check the weekday again. Do not assume the dates match, and do not use the time difference on your arrival day to calculate a trip several months later. If your trip crosses a clock-change date, the outbound and return journeys may need different time differences. A conversion table is useful for a quick understanding, but verify the final appointment with a tool that supports city time zones.
Do not apply another US city’s time difference directly to Denver
The United States has several time zones, and not every location follows the same clock-change rules. “Morning in the US” is not enough information to arrange a pickup. If a booking confirmation or a friend’s message gives only a time, add the city and date. If the departure and destination are in different time zones, manage each ground-transport leg using the local time at its location.
Most of Arizona does not observe daylight saving time, so Phoenix time cannot be treated as Denver time throughout the year. The two cities sometimes show the same clock time and sometimes differ by one hour. Cross-check this distinction using NIST’s Local Time FAQs and city time zone data. Even if you are flying or driving into Denver from a nearby state, check the destination clock again.
Airline, lodging, and pickup documents may display times in different ways. Look for “local time,” a time zone abbreviation, or a city name; do not automatically treat a nine o’clock time as Taipei time. If one booking lists times for both cities, both entries should point to the same moment. If the conversions do not agree, ask the booking provider to confirm before putting the conflicting information in your calendar.
Choose a city time zone for your phone and calendar
Add Denver to your phone’s world clock and keep Taipei there as a comparison. For calendar events, choose Denver’s city time zone or, on supported systems, America/Denver. Do not fix every event throughout the year to UTC−07:00. A city time zone lets a system with applicable time zone data determine the offset by date; a fixed UTC offset is a number that does not change with the rules.
When saving a hotel pickup or event, first confirm which city the event belongs to, then enter its local date and time. After your phone changes its displayed time zone during travel, the same event may appear with the clock time used at your new location. That does not necessarily mean the appointment itself changed. Open the event details to check its original settings and time zone instead of creating a duplicate that is one hour off. Google Calendar’s official time zone help also notes that time zone rule updates may affect existing events, so confirm important appointments again.
Keep appointments and daily plans aligned before and after arriving in Denver
For arrival day, record “transport arrival time” and “earliest check-in time” separately. A time zone conversion tells you the clock time and date; it cannot tell you whether a hotel will allow early check-in, and an airport landing time is not the same as having reached downtown. When coordinating a pickup, confirm the flight, arrival date, and meeting point together, then leave enough time for the actual journey.
When contacting family in Taipei, choose a time format both sides can understand in advance, such as “Monday evening in Denver, Tuesday morning in Taipei,” and add the exact date before departure. This gives you a shared record that is easy to check even if your phone automatically changes its displayed time zone during the trip. If you need to change the call time, update the original record to avoid having one version agreed verbally and another in the calendar.
When planning a city walk, consider civil time and daylight separately. The clock alone cannot tell you when it will get dark, what the temperature will be, or whether an attraction is open. Before heading out, return to the Denver city page for time and daylight information; check transportation and venue details separately. Confirming appointment times before planning travel and rest makes the day easier to manage than packing every activity into arrival day.
Further reading and sources
Event dates, opening hours, and transport services may change. Check official updates before you travel.
