Istanbul and Vienna Time Zone Comparison
Istanbul and Vienna are two major cities that sit in noticeably different time zones. Istanbul and Vienna sit on different continents, in noticeably different time zones, and at least one of them observes daylight saving time.
Because Istanbul and/or Vienna observe daylight saving time for part of the year, the gap between them isn't fixed — it ranges between 1 and 2 hours depending on the season.
With such a small gap, scheduling a call between Istanbul and Vienna is easy — a normal business-hours slot works for both sides on the same calendar day.