What Time Zone Is Chōfu In?
Chōfu operates on Asia/Tokyo, abbreviated as GMT+9, which is currently UTC+09:00 from Coordinated Universal Time. The IANA Time Zone Database (also known as the tz database or zoneinfo) records this under the identifier Asia/Tokyo. That identifier is what your phone, laptop, and every major web service uses when they display a localized time for Chōfu.
The designation Asia/Tokyo follows the IANA convention of naming zones after the largest city in that timezone region. This naming is geographic, not political, it reflects where the zone is observed, not which government controls it. The full record for this zone, including historical UTC offsets and past DST rule changes, is publicly available in the Wikipedia list of tz database time zones.
UTC Offset: Chōfu vs. The World
The current UTC offset in Chōfu is UTC+09:00. This means Chōfu time is 09:00 hours ahead of Coordinated Universal Time. To quickly convert: if it's 12:00 UTC right now, it's 03:46 local time in Chōfu.
Relative to other major cities: Chōfu is 14 hours ahead of New York, and 9 hours ahead of London (including any DST difference currently in effect). These differences can shift by one hour during DST transitions, which occur on different dates in different regions.
Business Hours in Chōfu
Standard business hours in Chōfu run from 09:00 to 18:00 local time (Asia/Tokyo). In UTC, that window is 00:46 to 09:46 UTC. If you're trying to schedule a call with someone in Chōfu:
- From New York: the Chōfu business day runs 19:46 to 04:46 New York time.
- From London: the Chōfu business day runs 00:46 to 09:46 London time.
Use the hour-by-hour conversion table above for the full 24-hour breakdown.
Daylight Saving Time in Chōfu
The DST indicator above shows whether Chōfu currently observes Daylight Saving Time. When DST is active, clocks advance by one hour, shifting the UTC offset by +1 and changing the abbreviation (for example, from EST to EDT in New York). When DST ends, clocks fall back and the offset returns to its standard value.
Not all countries observe DST. Japan, China, India, most of Africa, and several other nations maintain a fixed offset year-round. Whether Asia/Tokyo observes DST, and the exact dates of transitions, is governed by the rules stored in the IANA Time Zone Database , the same source your phone uses. The Wikipedia article on Daylight Saving Time provides a global map and country-by-country breakdown of DST observance.
Sunrise and Sunset in Chōfu
Today in Chōfu (35.7°N, 139.5°E), sunrise is approximately 06:11 and sunset is approximately 17:36 local time (Asia/Tokyo). These times are calculated using the Spencer equation for solar declination and apply to today's date. Latitude significantly affects day length: cities near the equator see roughly 12 hours of daylight year-round, while high-latitude cities experience dramatic swings, midsummer days can exceed 20 hours near the Arctic Circle, while midwinter days shrink to under 4 hours. At 35.7° latitude, Chōfu's day length varies by several hours between summer and winter solstice.
Best Time to Call Chōfu from Abroad
Standard business hours in Chōfu run 09:00 to 18:00 local time (Asia/Tokyo). For international callers, the ideal window is 10:00 to 16:00 Chōfu time : after the morning rush and before the end-of-day slowdown. In UTC, this translates to 01:46 to 07:46 UTC. Avoid calling before 09:00 or after 20:00 Chōfu time, these windows fall outside acceptable business etiquette in most professional settings. If you are calling from New York,Chōfu business hours correspond to 19:46 to 04:46 Eastern time. From London, that same window is 00:46 to 09:46 GMT/BST.
Chōfu Time vs Major World Cities
Right now, Chōfu (UTC+09:00) is offset from major business hubs as follows:
- New York: Chōfu is 14 hours ahead of New York right now (UTC-05:00).
- London: Chōfu is 9 hours ahead of London right now (UTC+00:00).
- Dubai: Chōfu is 5 hours ahead of Dubai right now (UTC+04:00).
- Singapore: Chōfu is 1 hour ahead of Singapore right now (UTC+08:00).
- Tokyo: Chōfu is the same time as Tokyo right now (UTC+09:00).
- Sydney: Chōfu is 2 hours behind Sydney right now (UTC+11:00).
These differences shift by one hour during DST transitions, which occur on different dates in different regions. Always verify the current offset before scheduling.
Geographic Location of Chōfu
Chōfu sits at 35.6592°N, 139.5484°E. Solar noon, the moment the sun reaches its highest point, occurs at approximately 11:46 local time, when the sun crosses the meridian above Chōfu. The IANA timezone Asia/Tokyo groups Chōfu with nearby cities that share the same legal time, even if they sit at slightly different longitudes and therefore experience solar noon at slightly different moments. Zone boundaries are drawn along political borders and transportation corridors, not strict meridian lines.
Chōfu: Size, Population, and Location
Chōfu has a population of approximately 242,614 people, placing it among significant regional cities. The city sits at 35°39'N, 139°32'E (decimal: 35.6592°, 139.5484°),35.7 degrees north of the equator.
At 35.7° latitude, Chōfu experiences moderate seasonal variation in day length, expect roughly 9-10 hours of daylight in winter and 14-16 hours in summer. Today, Chōfu sees sunrise at 06:11 and sunset at 17:36 local time. The IANA timezone Asia/Tokyo groups Chōfu with nearby cities that share the same legal clock, even if they sit at slightly different longitudes with marginally different solar noon times.
Working Hours Overlap: Chōfu and Key Partners
Chōfu's standard working day (09:00–18:00 local, Asia/Tokyo) translates to different hours for common international partners:
- San Francisco (America/Los_Angeles): Chōfu's workday runs 16:46 to 01:46 Pacific time.
- Berlin (Europe/Berlin): Chōfu's workday runs 01:46 to 10:46 Central European time.
Overlap windows, times when both cities are within 09:00–18:00, are the practical window for real-time collaboration. Use the time difference tool on this site to find the shared working window for any pair of cities.