There is no time difference between Frankfurt and Munich. Both cities use Central European Time (CET, UTC+1 in winter and CEST, UTC+2 in summer). When it's 9:00 AM in Frankfurt, it's also 9:00 AM in Munich.
Both cities are in Germany and 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 - 5:00 PM) without any time conversion needed.
Frankfurt and Munich are Germany's two largest financial and business centers, connected by high-speed ICE trains in about 3.5 hours. Frankfurt is the banking capital while Munich is strong in automotive and technology.