For the last couple weeks my WiFi has been going to absolute crap almost every night around 7–8pm.
During the day it’s totally normal. I can work, stream, game, whatever. Then evening hits and suddenly videos buffer every few minutes, my phone randomly says there’s no internet, and the laptop connection gets painfully slow. Sometimes it lasts an hour, sometimes most of the evening.
I’ve already called my ISP a few times. They replaced the modem/router, checked the line and said everything looks fine on their end. Same problem with the new equipment. At first I thought the whole internet connection was dropping, but now I’m not so sure. What should I actually test next? Kinda losing my mind here.
First figure out whether you’re losing internet or losing WiFi. Those aren’t the same thing.
Next time it happens, plug a laptop directly into the router with Ethernet and see if that connection dies too. If wired is fine while WiFi is falling apart, your ISP can replace modems until Christmas and it won’t fix the problem.
@auto.loser Okay, just caught it happening tonight and tested this. Ethernet stayed completely normal. Speed was around 480 Mbps wired while my laptop on WiFi in the same room was bouncing between like 15–60 and buffering YouTube. So yeah… apparently I’ve been yelling at the ISP for the wrong thing 
Does this happen around the same time every night? If yes, are you in an apartment building?
@auto.loser Yep. Large apartment building and I can see a stupid number of networks from here. And the timing is weirdly consistent. Before 6 it’s usually fine, after 8 it’s a mess.
I’d actually scan it while the problem is happening. NetSpot works for this. Check the channels and nearby networks during the afternoon when everything is good, then check again around 8pm. Look at your own signal too, but especially how many strong neighboring APs are sitting on or overlapping your channel. Don’t just run it once at 11am and assume that’s what the air looks like all day. If your router is on Auto it may also be making some… questionable decisions.
@auto.loser I’ll scan it today when I get back from work.