You can test using the yahoo weather api which sends you the response in (also)JSON
Yahoo API is not supported anymore you can try ClimaCell API which is free for a developer account. I have been using this for my many projects or you can write a wrapper around this API to suit your needs.
They have pretty detailed documentation with sandbox testing if you would like. I found their forecast is very accurate and it goes back by 20 years if you want to work with big data or analyze historical climate change.