To get an API key for OpenWeather:
- Visit OpenWeatherMap pricing page choose your plan and subscribe. You can choose the free plan to start, signup clicking here http://home.openweathermap.org/users/sign_up.
- Fill up the form and submit, you will be logged in automatically and receive an email with some useful information about the API.
- Now you can click on “API keys” menu where you will find a key that you can use straight away. You can also create more keys.