Miami is 5 hours behind Reykjavik
Best overlap: 1:00 PM to 6:00 PM in Reykjavik is 8:00 AM to 1:00 PM in Miami.
Shoot for 1:00 PM to 6:00 PM in Reykjavik; your Miami colleagues will see that as 8:00 AM to 1:00 PM. Miami is 5 hours behind Reykjavik, so you've got a workable 5-hour overlap — ideal for a standing meeting around 1:00 PM in Reykjavik (8:00 AM in Miami). For part of the year the maths changes: Miami observes daylight saving, Reykjavik does not, shifting the overlap by an hour.