Istanbul, Turkey · UTC+3 ☆

Istanbul runs on UTC+3 year-round. In September 2016, Turkey permanently adopted what had been summer time and abolished the winter clock change. The country moved from the European standard (UTC+2 winter, UTC+3 summer) to a fixed UTC+3.

The decision was politically charged. Critics argued it made Turkey an outlier in relation to European trading partners, since most of Europe stays at UTC+1 in winter. In practical terms, Istanbul’s business day begins when London is at 5am and Frankfurt is at 6am, creating a short overlap window in the morning.

The city across two continents

Istanbul straddles the Bosphorus strait, with the historic peninsula and most of the city on the European side and the Asian districts of Üsküdar and Kadıköy on the other. The Bosphorus bridge connects two continents. The same UTC+3 timezone covers both sides.

At 41 degrees North, Istanbul has noticeable seasonal variation. Permanent UTC+3 means summer solar noon falls around 1:15pm, a significant offset from solar time. In winter, that same noon arrives at about 12:20pm, but under the old UTC+2 it would have been a more natural 11:20am.

Ottoman time and the Islamic calendar

Under the Ottoman Empire, Istanbul operated on a time system where midnight was defined as sunset and the clock was reset daily with the call to prayer. This “alaturka” time coexisted with European clock time in the cosmopolitan city and was only fully replaced by the Republic in 1925 as part of Atatürk’s modernization reforms.

Convert 9am Istanbul time to other cities.

Sources

• IANA Time Zone Database
• Turkish Statistical Institute
• Mansel, Philip. Constantinople: City of the World’s Desire, 1453-1924. St. Martin’s Press, 1995.