Havana and Cancun are in the same time zone. Both cities use Eastern Standard Time (EST, UTC-5). When it's noon in Havana, it's also noon in Cancun.
Both observe daylight saving time, switching to UTC-4 in summer.
Any time works! Since both cities are in the same time zone, scheduling is never an issue.
Havana and Cancun are both Caribbean destinations. They are separated by about 500 km across the Yucatan Channel.