As amazing as the built in WordPress RSS widget can be there are times that it just doesn’t update fast enough. Thanks to the fact that WordPress is so easy to customize we can easily change this. In this article, we will show you how to alter the WordPress RSS Widget’s refresh rate.
All you have to do is add the following code to your theme’s functions.php file or into a site-specific plugin:
add_filter( 'wp_feed_cache_transient_lifetime', create_function('$a', 'return 600;') );
In this example it is set to refresh every 600 seconds, or 10 minutes. Simply change this number to whatever you want and your RSS widget will refresh accordingly.