Olivier drew these background for Spera official website -> http://spera-comic.com/

 

As you can see, the backgrounds change when winter comes. You can even see some falling  snow when the season requires it. During the rest of the year, you can see floating clouds and the Spera characters (drawn by Afu Chan) are sitting in the sceneries. 

 

Spera is an ongoing fantasy comic detailing the adventures of two princesses – Pira and Lono – . Fleeing their homelands after a cataclysmic event, the trio turn their escapist fantasies into a stranger reality, venturing into a land of which they had only ever heard the tallest tales.

Written, created and edited by Josh Tierney, Spera is a collaboration between artists from around the world. 

You can find a lot of free short comics on the website.