@sdetweil I couldn’t choose the old 2.5 API when I registered as new user to OpenWeatherMap. Therefore I had no other chance than to go with the 3.0 API.

@chief depending on the API you are subscribed to, you need to edit the node_helper.js (as mentioned in my previous post). After editing you should restart your magicmirror.

Hey @ally, I recently ran into the same problem like you.
I followed all instructions given to you from @sdetweil and finally figured out, what the problem was: openweathermap updated its api to version 3.0!
Even if you have a free subscription (limiting to 1000 api-calls a day, which is fine unless you stay above a refreshrate of every 3 minutes), you need to edit the link in node_helper.js from

var url = "https://api.openweathermap.org/data/2.5/onecall" +

to

var url = "https://api.openweathermap.org/data/3.0/onecall" +

For the free subscription on API-Version 3.0, you need to provide your credit card information, but you can set the maximum of possible API-calls to 1000, so that you will never ever ran into any costs.