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.

joshmccarty

Flurry adds a falling snow effect to your WordPress site. It uses the <a href="https://github.com/joshmcrty/flurry" rel="nofollow ugc">Flurry jQuery plugin</a> to create the effect. <a href="https://cdn.rawgit.com/joshmcrty/Flurry/master/index.html" rel="nofollow ugc">See an example</a>.
The Flurry jQuery plugin takes advantage of CSS <code>transforms</code>, CSS <code>transitions</code> and <code>requestAnimationFrame</code> to provide smooth animation for modern browsers. It uses unicode characters as snowflakes, with no dependencies on images or CSS files. Polyfills are automatically provided for <code>requestAnimationFrame</code> and CSS <code>transitions</code> (falling back to <code>setInterval</code> and jQuery’s <code>.animate()</code> feature respectively) for excellent browser compatibility. See the <a href="https://github.com/joshmcrty/flurry" rel="nofollow ugc">Flurry website</a> for more information.

Flurry

Adds falling snow to your site using the Flurry plugin for jQuery.

Snowfall vs Flurry