All requests require a free API key (sometimes called "APPID") from OpenWeaterMap. To retrieve your API key, sign up for an OpenWeatherMap account.
Please also take note of the license OpenWeatherMap provides the data under. At the time of writing, all data is licensed under the CC BY-SA 4.0, even for paid accounts. However, remember that this project is not affiliated with OpenWeatherMap, this information may be outdated and I can't give you legal advice. Make sure to check on the terms and conditions yourself:
If something with your API key or account does not work as expected, please contact OpenWeatherMap directly instead of opening an issue, since I most likely cannot help you with your account.