Iran operates on Iran Standard Time (IRST) in winter, which is 3 hours and 30 minutes ahead of Coordinated Universal Time (UTC+3:30). During summer, Iran observes Iran Daylight Time (IRDT), moving to UTC+4:30. This is one of only a few countries using a half-hour offset timezone.
Major cities including Tehran, Mashhad, Isfahan, Shiraz, and Tabriz all follow the same time.
Iran's unusual half-hour timezone was established to better align with solar noon in Tehran. Iran uses the Persian (Solar Hijri) calendar, which starts on the spring equinox (Nowruz). The country has 24 UNESCO World Heritage Sites, including the ancient ruins of Persepolis. Iran is one of the world's oldest civilizations, with a history spanning over 5,000 years.