Chicago
United States
--:-- --
CST · UTC-6 9 hours 30 minutes difference
Tehran
Iran
--:-- --
GMT+3:30 · UTC+3:30 Convert Chicago (CST) to Tehran (GMT+3:30) Time — 9 hours 30 minutes apart
America/Chicago · CST · UTC-6 | Asia/Tehran · GMT+3:30 · UTC+3:30 · 9 hours 30 minutes difference · 413 cities · DST applies
24-Hour Overlap Timeline
❌ No business-hours overlap between Chicago and Tehran (9–18 local)
⚠ Chicago observes daylight saving time — offset may vary by up to 1 hour seasonally
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UTC → | ||||||||||||||||||||||||
| 🇺🇸 Chicago UTC-6 | 6p | 7p | 8p | 9p | 10p | 11p | 12a | 1a | 2a | 3a | 4a | 5a | 6a | 7a | 8a | 9a | 10a | 11a | 12p | 1p | 2p | 3p | 4p | 5p |
| 🇮🇷 Tehran UTC+3:30 | 3a | 4a | 5a | 6a | 7a | 8a | 9a | 10a | 11a | 12p | 1p | 2p | 3p | 4p | 5p | 6p | 7p | 8p | 9p | 10p | 11p | 12a | 1a | 2a |
Both working Working Off hours Sleeping Now
Key Facts: Chicago (CST) vs Tehran (GMT+3:30)
Time Gap
9h 30m
Tehran ahead
May vary ±1h (DST)
DST Status
⏰ Chicago
Observes DST
✅ Tehran: No DST
Cities in CST
250
Largest: Chicago
8,489,066 pop.
Overlap Window
None
No work-hour overlap
Consider early/late meetings
Find Cities in Chicago & Tehran Timezones
The CST and GMT+3:30 timezones are separated by 9 hours 30 minutes. Chicago is the largest city in the America/Chicago zone and Tehran is the largest in Asia/Tehran. Chicago observes daylight saving time — the difference may change by 1 hour seasonally. For scheduling between these regions, the key fact is: there is no comfortable overlap during standard business hours.
Best Times to Schedule Calls: Chicago (CST) ↔ Tehran (GMT+3:30)
| Chicago (CST) | Tehran (GMT+3:30) | Quality |
|---|---|---|
| 12:00 AM | 9:00 AM | ❌ |
| 1:00 AM | 10:00 AM | ❌ |
| 2:00 AM | 11:00 AM | ❌ |
| 3:00 AM | 12:00 PM | ❌ |
| 4:00 AM | 1:00 PM | ❌ |
| 5:00 AM | 2:00 PM | ❌ |
| 6:00 AM | 3:00 PM | ❌ |
| 7:00 AM | 4:00 PM | ⚠️ |
| 8:00 AM | 5:00 PM | ⚠️ |
| 9:00 AM | 6:00 PM | ⚠️ |
| 10:00 AM | 7:00 PM | ⚠️ |
| 11:00 AM | 8:00 PM | ❌ |
| 12:00 PM | 9:00 PM | ❌ |
| 1:00 PM | 10:00 PM | ❌ |
| 2:00 PM | 11:00 PM | ❌ |
| 3:00 PM | 12:00 AM +1 day | ❌ |
| 4:00 PM | 1:00 AM +1 day | ❌ |
| 5:00 PM | 2:00 AM +1 day | ❌ |
| 6:00 PM | 3:00 AM +1 day | ❌ |
| 7:00 PM | 4:00 AM +1 day | ❌ |
| 8:00 PM | 5:00 AM +1 day | ❌ |
| 9:00 PM | 6:00 AM +1 day | ❌ |
| 10:00 PM | 7:00 AM +1 day | ❌ |
| 11:00 PM | 8:00 AM +1 day | ❌ |
Work hours defined as 09:00–18:00 local time. ✅ Both in work hours ⚠️ Borderline ❌ Outside work hours.
CST to GMT+3:30: Complete 24-Hour Time Conversion Table
| Chicago (CST) | Tehran (GMT+3:30) | IST (UTC+5:30) |
|---|---|---|
| 12:00 AM | 9:30 AM | 11:30 AM |
| 1:00 AM | 10:30 AM | 12:30 PM |
| 2:00 AM | 11:30 AM | 1:30 PM |
| 3:00 AM | 12:30 PM | 2:30 PM |
| 4:00 AM | 1:30 PM | 3:30 PM |
| 5:00 AM | 2:30 PM | 4:30 PM |
| 6:00 AM | 3:30 PM | 5:30 PM |
| 7:00 AM | 4:30 PM | 6:30 PM |
| 8:00 AM | 5:30 PM | 7:30 PM |
| 9:00 AM | 6:30 PM | 8:30 PM |
| 10:00 AM | 7:30 PM | 9:30 PM |
| 11:00 AM | 8:30 PM | 10:30 PM |
| 12:00 PM | 9:30 PM | 11:30 PM |
| 1:00 PM | 10:30 PM | 12:30 AM |
| 2:00 PM | 11:30 PM | 1:30 AM |
| ← Date changes in Tehran → | ||
| 3:00 PM | 12:30 AM +1 | 2:30 AM |
| 4:00 PM | 1:30 AM +1 | 3:30 AM |
| 5:00 PM | 2:30 AM +1 | 4:30 AM |
| 6:00 PM | 3:30 AM +1 | 5:30 AM |
| 7:00 PM | 4:30 AM +1 | 6:30 AM |
| 8:00 PM | 5:30 AM +1 | 7:30 AM |
| 9:00 PM | 6:30 AM +1 | 8:30 AM |
| 10:00 PM | 7:30 AM +1 | 9:30 AM |
| 11:00 PM | 8:30 AM +1 | 10:30 AM |
IST (India Standard Time, UTC+5:30) shown as reference for Indian users. +1/−1 indicates a different calendar day.
250 Cities in Chicago (CST) & 163 Cities in Tehran (GMT+3:30) — Page 1 of 2
Chicago & 249 more — Chicago (CST, UTC-6)
- Chicago, US 8.5M
- Houston, US 6.0M
- Dallas, US 5.8M
- Minneapolis, US 2.9M
- St. Louis, US 2.1M
- San Antonio, US 2.1M
- Austin, US 1.9M
- Kansas City, US 1.7M
- Milwaukee, US 1.3M
- Nashville, US 1.2M
- Memphis, US 1.0M
- Oklahoma City, US 1.0M
- Fort Worth, US 941K
- New Orleans, US 919K
- Omaha, US 826K
McAllen, USBirmingham, USWinnipeg, CATulsa, USBaton Rouge, USReynosa, MXDes Moines, USHeroica Matamoros, MXWichita, USLittle Rock, USMadison, USDenton, USFayetteville, USPensacola, USArlington, USNuevo Laredo, MXHuntsville, USCorpus Christi, USJackson, USMobile, USSt. Paul, USLincoln, USSpringfield, USPlano, USLubbock, USDavenport, USShreveport, USRockford, USPeoria, USKilleen, USLaredo, USIrving, USRound Lake Beach, USMontgomery, USGarland, USAppleton, USGulfport, USLafayette, USGreen Bay, USFargo, USBrownsville, USClarksville, USCollege Station, USFrisco, USSioux Falls, USEvansville, USAmarillo, USGalveston, USMcKinney, USGrand Prairie, USWaco, USOverland Park, USCedar Rapids, USMurfreesboro, USAurora, USPanama City, USPiedras Negras, MXTuscaloosa, USOdessa, USCiudad Acuna, MXTopeka, USJoliet, USNaperville, USPasadena, USMesquite, USChampaign, USHouma, USBeaumont, USLake Charles, USOlathe, USMidland, USColumbia, USMetairie, USRacine, USBloomington, USCarrollton, USTyler, USIowa City, USNorman, USFort Smith, USLewisville, USAbilene, USPearland, USKenosha, USRound Rock, USTemple, USRochester, USIndependence, USDuluth, USRichardson, USMonroe, USThe Woodlands, USSt. Cloud, USBroken Arrow, USHarlingen, USMandeville, USLeague City, USPort Arthur, USElgin, USWaterloo, USSioux City, USLongview, USSugar Land, USEau Claire, USAuburn, USAllen, USLee's Summit, USEdinburg, USWichita Falls, USBowling Green, USCiudad Rio Bravo, MXSan Angelo, USBismarck, USNew Braunfels, USConroe, USLawrence, USEdmond, USSlidell, USAtascocita, USLa Crosse, USO'Fallon, USHoover, USLawton, USWaukegan, USJoplin, USSpringdale, USMission, USBryan, USFranklin, USDecatur, USBaytown, USBrooklyn Park, USCicero, USHattiesburg, USOwensboro, USFlorence, USPharr, USPlymouth, USJonesboro, USGeorgetown, USTexarkana, USFlower Mound, USAlton, USCedar Park, USHammond, USWoodbury, USSchaumburg, USEvanston, USSt. Joseph, USWausau, USAnniston, USArlington Heights, USOshkosh, USMansfield, USMissouri City, USJanesville, USSan Marcos, USDothan, USSherman, USBolingbrook, USAlexandria, USSheboygan, USLakeville, USRogers, USBlaine, USSt. Charles, USWaukesha, USAnkeny, USMaple Grove, USNorth Richland Hills, USConway, USWest Des Moines, USSpring Hill, USGrand Forks, USMichigan City, USGary, USValle Hermoso, MXDubuque, USShawnee, USEagan, USKankakee, USLeander, USSpring, USPalatine, USVictoria, US
Tehran & 162 more — Tehran (GMT+3:30, UTC+3:30)
- Tehran, IR 14.1M
- Mashhad, IR 3.7M
- Esfahan, IR 2.2M
- Karaj, IR 2.0M
- Shiraz, IR 1.6M
- Tabriz, IR 1.6M
- Ahvaz, IR 1.3M
- Qom, IR 1.2M
- Kermanshah, IR 947K
- Kerman, IR 738K
- Orumiyeh, IR 736K
- Borvayeh-ye Al Bu `Aziz, IR 690K
- Rasht, IR 680K
- Bahar, IR 673K
- Zahedan, IR 588K
Hamadan, IRYazd, IRArdabil, IRBandar `Abbas, IRArak, IREslamshahr, IRSanandaj, IRQazvin, IRZanjan, IRGorgan, IRShahriar, IRShahr-e Qods, IRKashan, IRMalard, IRMaragheh, IRSarta, IRDezful, IRBabol, IRQa'em Shahr, IRKhomeyni Shahr, IRSabzevar, IRAndimeshk, IRAmol, IRPakdasht, IRNajafabad, IRBorujerd, IRMadan, IRQarchak, IRBojnurd, IRVaramin, IRBandar-e Bushehr, IRNeyshabur, IRSaveh, IRBirjand, IRNasim Shahr, IRKhorramabad, IRKhowy, IRBukan, IRShahr-e Kord, IRSemnan, IRFardis, IRSirjan, IRShahin Shahr, IRMalayer, IRMahabad, IRSaqqez, IRShahrud, IRKhodabandeh, IRBandar-e Mahshahr, IRRafsanjan, IRBorazjan, IRGonbad-e Kavus, IRMarvdasht, IRQuchan, IRJahrom, IRKamalshahr, IRTorbat-e Heydariyeh, IRMarivan, IRShahreza, IRZabol, IRKhorramshahr, IRMarand, IRJiroft, IRSalmas, IRBam, IRBehbahan, IRDorud, IRNazarabad, IRMohammad Shahr, IRBandar-e Anzali, IRIranshahr, IRFasa, IRBaneh, IRYasuj, IRChabahar, IRRobat Karim, IRKashmar, IRShushtar, IRAhar, IRMasjed Soleyman, IRTorbat-e Jam, IRAbhar, IRMianeh, IRDo Gonbadan, IRKazerun, IRBehshahr, IRAlvand, IRPiranshahr, IREslamabad-e Gharb, IRKuhdasht, IRFulad Shahr, IRKhowrasgan, IRTajrish, IRShirvan, IRMeybod, IRTakestan, IRLangarud, IRBumahen, IRBaharestan, IRAligudarz, IRBandar-e Emam Khomeyni, IRBandar Emam, IRQorveh, IRShush, IRNahavand, IRBonab, IRArdakan, IRRamhormoz, IRMeshgin Shahr, IRBandar-e Genaveh, IRNaqadeh, IRKhomeyn, IROmidiyeh, IRAran Bidgol, IRBaqershahr, IRMahdasht, IRMobarakeh, IRMeshkin Dasht, IRNeka, IRKangan, IRAbyek, IRSaravan, IRBabolsar, IREsfarayen, IRDamghan, IRZarand, IRBorujen, IRDehdasht, IRKhash, IRTaybad, IRKut-e `Abdollah, IRZarrin Shahr, IRAsadabad, IRHashtgerd, IRTonekabon, IRKhorramdarreh, IREqbaliyeh, IRJavanrud, IRHashtpar, IRSefrou, MASabbashahr, IRBandar-e Torkaman, IRChenaran, IRBijar, IR`Aliabad-e Katul, IRKahnuj, IRSusangerd, IRTuyserkan, IR
⚠️ Daylight Saving Time Affects This Pair
| Timezone | DST? | Standard | Daylight |
|---|---|---|---|
| America/Chicago | Yes | UTC-6 | UTC-5 |
| Asia/Tehran | No | UTC+3:30 | — |
During DST periods the time difference between these zones may be 8 hours 30 minutes instead of 9 hours 30 minutes. Always verify the current offset if scheduling calls near clock-change dates.