Three emails were sent over the last week, ever since the temperature dropped in this area, to their support address over the same sort of network stability issues that I had around this time last year. No replies, no action taken, no nothing.
The theories were that either there was a problem with the hardware outside caused by the temp. change, and another was that the signal strength dropped because more people were staying inside and watching TV or getting online. Either way, it appears that signal strength was the problem, as I bought and installed a signal booster today and so far tonight things have been fine. It's happened nightly so far since the temp. dropped, so this seems like a good sign, but I'm going to wait a few days before calling the problem definitely fixed.
Thanks for nothing, Time Warner Cable.