Sorry to hear you're getting poor latency in the evenings. I've just checked your connection and can see no cause for this from here. Your power levels, SNR and area contention all show healthy when tested.
Thank you for playing wired that rules out all the complications that come with a wireless connection. Are you getting high ping with all games you play or only certain ones? If so could you run some traceroutes to the servers you play on and post them here for us to take a look at?