About the service from OpenWeatherMap.org you can get free weather data. In order to access this service automatically - for example from NodeRed or from an Arduino - you need an API key.
This article describes how to register it.
Register user login for OpenWeatherMap.org
In order to register an API key, you must first set up a user login. Go to the website OpenWeatherMap.org.
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Register API key
Once you have created your user account for OpenWeatherMap, you can now create an API key. An API key is a long string of characters that - similar to a username and password - gives you access to the services offered by OpenWeatherMap.
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You can now use this API key in your Arduino or RaspberryPi project to retrieve current weather data.
Have fun with the project
I hope everything worked as described for you. If not or you have questions or suggestions please let me know in the comments. I will then add this to the article if necessary.
Ideas for new projects are always welcome. 🙂
PS Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you think it's cool that I share the information with you, I would be happy about a small donation to the coffee fund. 🙂