You need the knowledge about the daily weather for your tour planing. It is quite hard to find one weather forecasting service who is always right with his predictions. That is because it such a complex topic. The easiest think you can do is to read the forecast of not just one service. We as guides read mostly 2-4 weather reports to see what could be possible.
Another good tool is the weather radar. There you can see the progress of the clouds and how the weather changes more in detail. The weather situation decides if yo can go away from the save groomed runs or if you have to stay
Forwarding to our weather specialist: Wetterring