Artyom Ilyin

Simple easy-to-use and easy-to-set-up lightweight plugin for snowfall effect on your site. If you have any questions or inqueries, please feel free to get in touch via email kupnoh25@gmail.com.
Snowfall plugin uses snowfall library to set up snow effect. For more info about the library go to https://github.com/KupnoH/snowfall. 
Plugin is very easy to install and use. 
Though some coding needed to set this plugin up it’s very easy and Installation section explains it in details. 
You can find this plugin on github <a href="https://github.com/KupnoH/snowfall-wp" rel="nofollow ugc">here</a>

Snowfall

Simple easy-to-use and easy-to-set-up lightweight plugin for snowfall effect on your site.

mohanjith

Code Master

Update Dec 23, 2012
Updated snow falll script to work with Wibiya. Localized Settings Page. Moved the Settings Page under main Settings. Uses register script and enque script.
Update Jan 30, 2011
Updated the plugin to the latest stable version of the snow script. Added additional options to the plugin admin page.
Update Nov 07, 2009
I have not been supporting this plugin for a long long time, almost 2 years in fact. Since Christmas is round the corner, I thought I should give this plugin a nice refresh. I have updated the snow script to the latest version. Best of all, I have added a plugin settings page so it’s easier for those who are not comfortable with tweaking code.
History
In 2007, WordPress.com introduced a <a href="http://wordpress.com/blog/2007/12/25/let-it-snow/" rel="nofollow ugc">falling snow options</a> for its users after <a href="http://photomatt.net/2007/12/23/falling-snow-script/" rel="nofollow ugc">Matt Mullenweg asked for a falling snow script</a>. Because the feature was only available to WordPress.com users and not self-hosted WordPress blogs, I took the falling snow code and made a plugin that exactly the same thing. All users needed to do was to download and activate the plugin to have beautiful falling snow flakes on the blogs.
<h3>Notes & Credits</h3>
The falling snow script used in this plugin is originally by <a href="http://www.schillmania.com/projects/snowstorm/" rel="nofollow ugc">Scott Schiller</a>. 
This plugin is originally written by <a href="http://aentan.com/" rel="nofollow ugc">Aen Tan</a> and later improved by <a href="http://mohanjith.com/" rel="nofollow ugc">S H Mohanjith</a>.
You should follow us on Twitter <a href="http://twitter.com/codemasteroy" rel="nofollow ugc">here</a>.

Improved Let It Snow!

Upload the plugin folder to your plugin directory and activate to see falling snow on your blog.

Snowfall vs Improved Let It Snow!