This never happened to me before the big outage on the 19th.

So I'm playing Overwatch, and I usually average around ~40ms. However, recently I've been experiencing ping spikes up to 80-100 ms that are always in groups of nine. This happens every 5 or so seconds.

I have ruled out problems with connecting to the server in general, as I've been abled to ping it with online tests just fine and no jitter. My Wifi is also working perfectly (ethernet is not viable for me).

Here is a video of it:

https://gfycat.com/plainloathsomegelada

I have also done a lot of separate PC-related performance enhancements to improve latency etc. and, of course, have turned the modem off and on again. No change!

Overwatch server is located in Chicago, but I have tried connecting to the LA server and I get the same behaviour with higher latency.

I suspect this is an ISP problem given that there are a lot of topics like this on the game's forum that are only answered with 'check with your ISP'.