The idea of this challenge is to make a map displaying a specific season, which is ideally not summer since it is the most common one.
My initial proposition was to make a (snowy) winter map specifically but some people might feel it's too constrained.
Snowy winter maps are challenging because of the limited amount of colours and even so in a black and white map.

Also, it could be possible to make a complete world map showing accurate seasons for each area: if it's winter in the north, it's summer in the south for example.
It sounds obvious but most world maps show us worldwide summer or with winter in the north and sometime in the south at the same time. So these maps are inaccurate.