Dusk

I'm very confused.  It's 8.30 pm.  It's dark outside (it already feels like the days are getting shorter - sunset is before 8 pm now).  And one of my neighbors has decided to start mowing his lawn.  Which is insane.  And not the first time this has happened.  Admittedly, most people round here have a sit down lawn mower - and he probably has one with lights.  But still, why cut the grass so late?  As well as disturbing the neighbors, it is asking for trouble.  What if he runs over something he shouldn't do but didn't see?  There is no reason not to do this when it's still light outside - it's not like it was a particularly hot day or anything.  Was this really the only time he had free to do this?  It all seems very strange to me.