What is going on with the internet at night?

In the morning, I can play a video game and register a perfectly normal latency. But, from 3pm - 2 am I am getting considerable and consistent lag. How is this happening? Is COX throttling my area? I haven't had an issue with this in 3 years with them and all of a sudden it is impossible to do anything online in the evening. It is not only me. Multiple people in my area are complaining about the same thing. People being on the internet isn't an acceptable excuse.