Just to confirm what usual commands are - do you include tracert in that list? As this is the only tool which can answer this. You would need a healthy node list to compare to, but at least it'll show who's at fault - your modem, ISP, intranet, internet or server. Either way, no one else as reported latency issues - so it's most likely on your route.
You'll need to do a tracert now for a healthy hop list. Then you can compare later, and see if the path is the same, and if so who's dropping the ball. If not then you can guess one of the nodes is probably offline, which can't be helped.