What Time Zone Is Fasā In?
Fasā operates on Asia/Tehran, abbreviated as GMT+3:30, which is currently UTC+03:30 from Coordinated Universal Time. The IANA Time Zone Database (also known as the tz database or zoneinfo) records this under the identifier Asia/Tehran. That identifier is what your phone, laptop, and every major web service uses when they display a localized time for Fasā.
The designation Asia/Tehran 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: Fasā vs. The World
The current UTC offset in Fasā is UTC+03:30. This means Fasā time is 03:30 hours ahead of Coordinated Universal Time. To quickly convert: if it's 12:00 UTC right now, it's 08:50 local time in Fasā.
Relative to other major cities: Fasā is 9 hours ahead of New York, and 4 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 Fasā
Standard business hours in Fasā run from 09:00 to 18:00 local time (Asia/Tehran). In UTC, that window is 05:50 to 14:50 UTC. If you're trying to schedule a call with someone in Fasā:
- From New York: the Fasā business day runs 00:50 to 09:50 New York time.
- From London: the Fasā business day runs 05:50 to 14:50 London time.
Use the hour-by-hour conversion table above for the full 24-hour breakdown.
Daylight Saving Time in Fasā
The DST indicator above shows whether Fasā 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/Tehran 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 Fasā
Today in Fasā (28.9°N, 53.6°E), sunrise is approximately 06:50 and sunset is approximately 18:24 local time (Asia/Tehran). 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 28.9° latitude, Fasā's day length varies by several hours between summer and winter solstice.
Best Time to Call Fasā from Abroad
Standard business hours in Fasā run 09:00 to 18:00 local time (Asia/Tehran). For international callers, the ideal window is 10:00 to 16:00 Fasā time : after the morning rush and before the end-of-day slowdown. In UTC, this translates to 06:50 to 12:50 UTC. Avoid calling before 09:00 or after 20:00 Fasā time, these windows fall outside acceptable business etiquette in most professional settings. If you are calling from New York,Fasā business hours correspond to 00:50 to 09:50 Eastern time. From London, that same window is 05:50 to 14:50 GMT/BST.
Fasā Time vs Major World Cities
Right now, Fasā (UTC+03:30) is offset from major business hubs as follows:
- New York: Fasā is 8.5 hours ahead of New York right now (UTC-05:00).
- London: Fasā is 3.5 hours ahead of London right now (UTC+00:00).
- Dubai: Fasā is 0.5 hours behind Dubai right now (UTC+04:00).
- Singapore: Fasā is 4.5 hours behind Singapore right now (UTC+08:00).
- Tokyo: Fasā is 5.5 hours behind Tokyo right now (UTC+09:00).
- Sydney: Fasā is 7.5 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 Fasā
Fasā sits at 28.9383°N, 53.6482°E. Solar noon, the moment the sun reaches its highest point, occurs at approximately 11:20 local time, when the sun crosses the meridian above Fasā. The IANA timezone Asia/Tehran groups Fasā 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.
Fasā: Size, Population, and Location
Fasā has a population of approximately 98,061 people, placing it among smaller but notable cities. The city sits at 28°56'N, 53°38'E (decimal: 28.9383°, 53.6482°),28.9 degrees north of the equator.
At 28.9° latitude, Fasā experiences moderate seasonal variation in day length, expect roughly 9-10 hours of daylight in winter and 14-16 hours in summer. Today, Fasā sees sunrise at 06:50 and sunset at 18:24 local time. The IANA timezone Asia/Tehran groups Fasā 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: Fasā and Key Partners
Fasā's standard working day (09:00–18:00 local, Asia/Tehran) translates to different hours for common international partners:
- San Francisco (America/Los_Angeles): Fasā's workday runs 21:50 to 06:50 Pacific time.
- Berlin (Europe/Berlin): Fasā's workday runs 06:50 to 15:50 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.