Here's an Idea that may be worth pursuing in the future.
Add several clothing upgrades to infantry units. Small Buff/nerfs could be applied to a given squad for being appropriately equipped for Summer/winter /Desert Jungle/
Camo etc. The upgrade would be available to all or select squads in every faction. The Squad blueprint library would require updating, Skins would need to be available. The game engine is easily enough modified to accomodate this change and the upgrades could be incrementally updated the same way as maps are being winterized.