Spring and fall frosts are a major concern for fruit growers. Even experienced farmers have hard times to manage this condition. It gets even more complicated when the parcels are scattered over an enormous valley on various altitudes.
Growing crops in the Alps does not make the situation more easy where cold air settles downward and has a tendency to collect at the bottom of the slopes. In combination with icy winds does it compound temperature loss.
In short, temperatures are hard to predict in such a situation. A well-considered temperature monitoring network is more than welcome.