Time Zones

Iran Standard Time (IRST)

Introduction

Iran Standard Time (IRST) is the time zone used in Iran. It has a unique time offset of UTC+03:30, which is different from the usual full-hour offsets observed in most other time zones. IRST is defined by the 52.5 degrees east meridian, which also defines the Iranian calendar.

Time Zone History

Iran Standard Time was established to align with the solar time at 52.5° east longitude. Before 1945, Tehran Mean Time (TMT) was used, which had an offset of UTC+03:25:44. In 1946, IRST was adopted with an offset of UTC+03:30. Between 1977 and 1978, Iran briefly used an offset of UTC+04:00 during daylight saving time. From 1979 to 1980, the country observed Iran Daylight Time (IRDT) with an offset of UTC+04:30. Daylight saving time was reintroduced in 1991 and observed until 2005, and again from 2008 until it was abolished in 2022. Since then, Iran has observed standard time year-round.

Geographical Coverage

Iran Standard Time is observed throughout the entire country of Iran. The country spans a vast geographical area, but maintains a single time zone for simplicity. The reference meridian for IRST is 52.5° east longitude, which runs about 400 km (250 miles) east of Tehran.

Daylight Saving Time (DST)

Iran no longer observes daylight saving time. DST was previously observed between 1978 and 1980, 1991 and 2005, and 2008 and 2022. During DST, the clocks were set forward by one hour to UTC+04:30. The dates of DST transitions were based on the Solar Hijri calendar, with DST starting on 1 Farvardin (around March 21) and ending on 30 Shahrivar (around September 21).

Major Cities

Some of the major cities within the Iran Standard Time zone include:

  • Tehran: The capital city of Iran, known for its bustling metropolis and landmarks such as the Azadi Tower and Golestan Palace.
  • Mashhad: A major pilgrimage city, home to the Imam Reza Shrine.
  • Isfahan: Known for its stunning Persian architecture, including the Naqsh-e Jahan Square and the Si-o-se-pol Bridge.
  • Shiraz: Famous for its gardens, poets, and the ancient ruins of Persepolis.
  • Tabriz: An important historical city with landmarks like the Blue Mosque and the Tabriz Historic Bazaar Complex.

Local Culture and Traditions

Iran has a rich cultural heritage deeply rooted in its history and traditions. Persian (Farsi) is the official language, and Shia Islam is the dominant religion. Iranian culture is known for its poetry, miniature painting, and classical music. Hospitality is highly valued, and offering tea is a common gesture of warmth. Traditional Iranian cuisine includes dishes like kebabs, khoresh (stews), and tahdig (crispy rice).

Local Events and Holidays

Significant local events and holidays in Iran include:

  • Nowruz: The Persian New Year, celebrated on the spring equinox with family gatherings, special foods, and traditional games.
  • Islamic Republic Day: Celebrated on April 1st, commemorating the establishment of the Islamic Republic in 1979.
  • Revolution Day: Celebrated on February 11th, marking the victory of the 1979 Islamic Revolution.
  • Imam Mahdi's Birthday: A religious holiday celebrated with prayers and festivities.

Other Names

Iran Standard Time is commonly abbreviated as IRST. It is also referred to as Iran Time (IT). During the periods when daylight saving time was observed, it was known as Iran Daylight Time (IRDT).

Interesting Facts

  • Iran Standard Time is one of the few time zones with a half-hour offset from UTC.
  • The reference meridian for IRST at 52.5° east longitude is also used to set the start of the Iranian calendar year, known as Nowruz.
  • Iran's unique time zone position gives it a distinct place on the world’s time map, being 30 minutes ahead of Iraq and Saudi Arabia, and 1.5 hours ahead of Turkey during standard time.