craigb
Could be backups starting for your ISP.
I think this could have some bearing on it, I get it at the same time too around midnight which of course due to time difference would be a different time of day to you guys.
Sometimes the connection slows to a crawl (or rather more of a crawl than usual) and sometimes I'll get a red light on my router that says the connection has dropped completely even though the carrier stays up.
It's been happening here for years to the point I just expect it now at around the witching hour.