When can you see candles?

[tinkthank]

I've noticed that the very same scouting unit scouting in different provinces will get different levels of feedback.
A scout or a priest (that is: not a spy, who yields more information) will not always, however, be able to tell you what the dominion situation is in a province she or he is in.
But maybe I am confused: maybe the chance of you being able to decipher the candles in a province depends on your dominion? Or maybe on how far away your dominion is in terms of provinces?
Sometimes I can see a largish red candle: -4 enemy dominion. But sometimes, even with a scout in the province, I just don't know squat about it.
Perhaps someone can help: Under what conditions can I see the (size of the red) candle of an enemy-controlled province?