I'm not sure whether this belongs to Software Issues forum or simply my luck, so here I go:

Put simply, in that 6 hours I don't encounter a single random dragon, and in that particular session I chose to go exploring. I went from Whiterun to Shor's Stone, and all the way to Dawnstar, and to Markarth. Not a single dragon. I reckon that exploring all over will at least trigger one dragon? In previous sessions, in which I chose to abuse Fast Travel, lots of random dragons roam the area (and promptly burn villagers to the ground)

I haven't updated to 1.2 (or 1.3), if it has anything to do with my situation? Also, dragon corpses disappear in my game, while it's something that update 1.2 is supposed to address

Dragons don't appear unless you've completed the quest you get from the Jarl of whiterun where you have to fight a dragon

Aye, some of us avoid that quest on purpose for a while, especially if we want our Lydia to be strong. I really wish followers matched your level...

I have Lydia watching my house

Like Moop says, you have to do that quest for the Jarl of Whiterun. Otherwise they don't trigger.

It's like in Oblivion how, until you visited Kvatch Oblivion gates wouldn't appear around the world. That Main Questline stage is what triggers Dragon encounters. Until you do it the game won't spawn them.

But the? Keep watching the skies.

Especially for them flying backwards...