Seasons?

I'm 40 hrs into the campaign and just discovered some maps have seasons?? I'm in the Alpine map and it was snow covered for the first hour or so, and then all the sudden all the snow begins to melt and everything turns green.

I caught the screenshot during the transition. Does this happen on any other map? Is it on a times cycle or triggered?

https://preview.redd.it/1ndswdss3n4g1.png?width=3241&format=png&auto=webp&s=4ede5fc425f98038f4f794eef5fb65b42c060ac4