CSS Weather Conditions

http://codepen.io/rolanddubois/full/PbpqBM/
No images, no svg, no JS (except drop-down to swap classes)
All CSS and a minimal HTML structure -
One div container holding four div layers:
<div>
<div> </div>
<div> <em> </em> </div>
<div> </div>
<div> <b> </b> </div>
</div>
Check out my code and enjoy switching weather conditions!