There is no time difference between Frankfurt and Zurich. Both cities use Central European Time (CET/CEST, UTC+1/+2). When it's 12:00 PM in Frankfurt, it's also 12:00 PM in Zurich.
Both cities observe daylight saving time on the same schedule, so they remain synchronized year-round.
Any time works! Since both cities share the same timezone, you can schedule calls during standard business hours (9:00 AM - 6:00 PM) without any time conversion needed.
Frankfurt and Zurich are both major European financial centers. Frankfurt hosts the European Central Bank, while Zurich is known for private banking. The train between them takes about 4 hours.