That’s 50 kilos of Komondor

I noticed that early in the morning my dog does not look out the window to see if it is still dark. Instead, she goes to the top of the stairs and looks down the stairwell. Apparently, if it is dark “down there” then it must be dark outside.

However, this morning at first light she looked down the stairs and was apparently unsure whether it was morning yet. So, then she looked outside and confirmed that it was indeed getting light.

If looking outside is the definitive check, why doesn’t she do that first?