Tehran is 1.5 hours ahead of Oslo
Best overlap: 8:00 AM to 5:00 PM in Oslo is 9:30 AM to 6:30 PM in Tehran.
Target 8:00 AM to 5:00 PM in Oslo, which lands at 9:30 AM to 6:30 PM for the Tehran side. Tehran is 1.5 hours ahead of Oslo, but you'd hardly notice — 9 hours of shared hours makes this feel like working in neighbouring time zones. Don't be caught out by clock changes — Oslo observes daylight saving and Tehran doesn't, so the offset varies by an hour through the year.