The problem is that in Chrome you need to serve your page over
https for the geolocation to work. And if you use
https for your main page, it is required to use
https for API requests as well. Since Openweathermap does not support
https requests, I would suggest using an API that does allow
https or, as @PortableStick suggested, to use cors-anywhere to overcome these
I believe the instructions were made before Chrome stopped geolocation access from
http and haven’t been changed since. Now, you can still use Openweatermap in combinationo with cors-anywhere, but it is a less ideal solution. That is why I suggest using a different API (if you haven’t started yet).
Many people are struggling with this project and it will be removed from the new curriculum. (Or added as bonus project).
You are going to be totally fine if you follow the instructions. But you will have to use something like cors-anywhere (something the instructions don’t mention).