WordPress Plugin
https://github.com/coder-karen/show_weather_widget

‘Show Weather’ is a WordPress Plugin for displaying the current weather using the Yahoo API. After installation, it creates a widget that can be added to any widget area of your website, allowing you to input the location of your choice (as text, or use the Yahoo Weather ID – WOEID – for that location) as well as creating a title for your widget. It was built with PHP, CSS and JSON. At the time of the build, I was unable to find any other plugins for WordPress utilising the Yahoo API that worked.
The source-code is available to view or download via Github: github.com/coder-karen/show_weather_widget
Here is a live demo of the show weather widget.