For me it mostly works out. I look at "Weather in detail" on ARSO:
http://meteo.arso.gov.si/met/sl/app/webmet >> Model forecast >> ALADIN >> Cloudiness and precipitation
In the forecast for the mountains it sometimes writes something about the height of cloudiness, i.e. mainly when it is just fog in the lowlands. If it is at all heights, of course it makes no sense. Here:
http://meteo.arso.gov.si/met/sl/weather/bulletin/mountain/ And it is good to follow those cloudiness maps for a few days in a row, to see a bit if they are 100% accurate regarding clouds or not

Today based on that I set off for Tromeja, because there was only in NW Slovenia a chance that there would be no clouds, and I hit the jackpot

And one such borderline case, say last November, when the only potential sunny area was around Krma and western Pokljuka. From Debele peči there was a fantastic view of Triglav through bands of clouds.
Well, I am not writing to brag, just as an example that it is possible even in unstable conditions to seek nice weather (blunders still happen) or to decide that it is really better to stay home or that there is no sense in driving to the other end of the country if I can walk in the fog at home.