Tehran is 1.5 hours ahead of Warsaw

Best overlap: 8:00 AM to 5:00 PM in Warsaw is 9:30 AM to 6:30 PM in Tehran.

For the smoothest call, aim inside 8:00 AM to 5:00 PM in Warsaw, i.e. 9:30 AM to 6:30 PM in Tehran. Tehran is 1.5 hours ahead of Warsaw, but with 9 hours of common ground you can hold morning or afternoon meetings without anyone working odd hours. Seasonal note: Warsaw uses daylight saving and Tehran doesn't, so double-check the times in your own months — they can move by an hour.