In V a full day was forty eight minutes. RDR2 was longer. It matters more than it sounds because it determines whether you experience a location at multiple times of day naturally or only when a mission puts you there.
With a map this size and this much water, night driving through the Keys is going to be a completely different thing to daytime. Has any number been given?
Accepted answer
RDR2 ran a longer cycle and it made the world feel bigger, because getting somewhere before dark was an actual consideration. With this much map I would expect them to go longer again.
No number given. V's forty eight minute day is the only figure anyone has, and it is from a different game on different hardware.
night in the swamp with an airboat and a torch. that is the entire pitch for the region and it needs a proper night to work
Night in a dead coastal town is a completely different atmosphere to night in a city and a long cycle is what lets you actually experience both.
Getting somewhere before dark being a consideration is exactly the thing I want and I could not articulate why the cycle length mattered.