Step 1: At the first visit the official OpenWeatherMap registration page and signup for an API key. After logging in to your user account there, you will see an API keys tab on the dashboard. Click that, and copy your API key.

Step 2: Login to your Joomla site’s admin control panel. Click Modules on the left. Find the SP Weather module in the list appeared. Click SP Weather, and that will take you to its backend. There you will find the API KEY field to enter your OpenWeatherMap API key. Paste the API key (which you’ve just got in step 1) in the API KEY field and save.

You can also adjust the module settings to modify the appearance of the weather update information on your site.

Remember to clear Joomla cache after module update.