lucille
It sure is. Love a winter approach into there. It's either CAVOK or no go. Simples.
Ahhh the good old temperature correction. Fortunately the Swiss and the Scandi ATC add a temperature correction to the altitude they give you. Rather reassuring with those rocks around. However, our FMS has a temperature correction function. Saves a lot of brain work. (Temp correction is another thing FOCA test you on for Samedan. FOCA also test your knowledge about Föhn winds too.)
Have you done Sion LSGS too?
So - I guess the point is that you just never know when you're going to need to know how to do some of these calculations - or at least know where to look it up.