Intermittent internet connection when cold

I'm having an issue with my internet connectivity that's been happening for over a year now.

Like the title says, the internet connection for the whole house gets spotty when it's cold. The connection goes down for anywhere between 1 minute to several hours at a time depending on the day.

Wireless, wired, all devices, including work laptops which makes working from home difficult and I have to rely on my mobile hotspot to stay connected when it goes down. 

We've had 4 or 5 different technicians out for this issue, several last year and two out again this last month. We've had a total of three different gateways and have swapped out everything from the ethernet cables to the switch we used to use at the gateway with no luck.

The techs who visited last year said it seemed the cables on the outside of the apartment got chewed up by squirrels and replaced it but said it would need buried again when it got warmer outside.

I assumed they did just that because the problem went away at the end of last winter only to immediately start back up again when it started getting cold.

Then the last technician that arrived two weeks ago said the cable looked like it hadn't been replaced in seventeen years, so I have no idea what's going on anymore. 

The problem tends to happen at night as this is when it gets colder, which of course never happens when the technicians are here for visits during the day. 

I'm hoping I can get some assistance, as I genuinely can't keep going around in circles with the automated system anymore. 

Currently my internet has been down for a few hours now with the outage map saying nothing's wrong. I have a technician visit scheduled for this Friday but at this point I don't have a lot of confidence in the issue ever being fixed.