+xIn my experience the maximum time the Flyable Conditions are shown is from current time to current time + 2 hours. The screen turns pink two hours later than now. So there is no planning available for later in the day or tomorrow or even later.
You can experiment with this by setting a take off time at your current time and then chose "Animate" in the Weather drop-down menu.
The flyable condition will be shown and you can pause or run the animation from the box at the bottom of the map.
The feature is only a short term "prediction".
See screenshot.
Not sure if all is right but it's the way I see it.
.

Seems correct to me too. I also tested and 2 hours is the maximum time, therefore the manual is not correct:
Pag 41 "The map will turn pink if there is no Flyable Conditions forecast data available
for the time period you have selected"
should be amended or better clarified about.
If during fly we can get Internet connection the time will be extended for another 2 hours, but very rarely internet is available at an altitude more than 3000 ft.
Other weather app are more useful, they have a forecast for a day or next days, would be good to see these forecast on SkyDemon.
I like SkySight or Windy, you can draw a route from departure and arrival, setting the speed to determine the flying time and the day and time to takeoff.
I have used them during this foggy season or low ceiling and it is reliable.