How do I time international discounts for different timezones?

As an e-commerce business operating globally, I'm struggling to coordinate time-sensitive discount campaigns across multiple international markets. I want to ensure that my promotions start and end precisely at the right moment for each timezone, preventing customer confusion and potential revenue loss. How can I effectively manage discount timing to create a seamless, fair experience for customers around the world, considering the complexities of different time zones, daylight saving changes, and regional variations?