Denver is 2 hours behind Miami year-round. Miami uses Eastern Time (EST/EDT, UTC-5/-4) while Denver uses Mountain Time (MST/MDT, UTC-7/-6). Both cities observe DST on the same schedule.
The consistent 2-hour difference makes scheduling easy between these two cities on opposite sides of the country.
Mid-morning Miami works well. 11:00 AM Miami is 9:00 AM Denver - both in prime business hours. For afternoon calls, 4:00 PM Miami is 2:00 PM Denver.
United Airlines, American, and Frontier operate frequent direct flights between Miami and Denver, taking about 4.5 hours. Denver is a major tech and outdoor recreation hub.